DeepSeek V4 vs Claude Opus 4.7 vs GPT-5.5: I Tested All Three on Real Business Tasks
Three frontier AI models all launched within a week of each other. I decided to spend two days putting them through the kind of tasks small business owners actually run.
By Sam Frost
Published Apr 27, 2026 · 8 min read

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Last week saw three of the biggest AI model launches of 2026. Anthropic shipped Claude Opus 4.7. OpenAI followed with GPT-5.5. Then DeepSeek dropped V2, an open-source model from China that costs roughly a tenth of what its American rivals charge.
If you run a business that uses AI for anything important: writing, coding, customer support, research, document analysis, you’ve got three new options to consider. Right now, most of the comparisons out there are benchmarks. Numbers that might look impressive on paper but mean nothing when it comes to helping you execute.
So I decided to run my own tests. Seven tasks pulled from the kind of work I do every day across my business. The same prompts for each.
Before I get into the business tests though, I wanted to start with something even simpler.
Test zero: a setup test, not a serious one
Before running the actual business tests, I wanted a quick gut-check. This is more of a warm up to set the scene before things get more rigorous. The prompt:
I want to wash my car. The car wash is 50 meters away. Should I walk or drive?
This is a question with one right answers: you drive. The car needs a wash. The results are an interesting illustration of each model’s personality. DeepSeek V4 Pro got it right and seemed to show a lighter side with some humor. GPT-5.5 also got it right and got there the fastest. Claude Opus 4.7 got it wrong and confidently.
One prompt, not a serious test. But important because it tracks with something I’ve noticed using Claude Opus 4.7: it’s more willing to push back and disagree with the user than previous versions, even though it can be wrong. DeepSeek leaned into personality, something it lacked in V3.2. GPT-5.5 was efficient to the point of bluntness, it has been accused of rambling on in previous versions.
With that out of the way, here’s the actual tests.
Test 1: handling a tricky customer support email
The first real test is something every business owner has to deal with: a customer wants something they’re not entitled to, and your job is to say no without causing even more problems. Here’s the prompt:
A customer has emailed us asking for a full refund on a $299 software subscription. They've used it for 3 weeks. Our refund policy is 14 days. They're claiming the software is 'much harder to use than expected' but our records show they've completed 4 of the 7 onboarding steps and used the product 12 times. Write a reply that declines the refund but offers a free 30-minute onboarding call instead. Tone should be empathetic but firm. Don't mention the policy by name like a robot, just explain naturally.
This is both a test of judgment and writing. The model has to hold a position the customer won’t like, do it without sounding like a robot, and pivot to something that will solve the customer’s complaint.
All three models passed the basic test, but the differences were shaper than I expected. DeepSeek V4-Pro produced the most send-ready email of the three, with a tight structure and nice reframe of the customer’s frustration into something positive. GPT-5.5, despite hitting every required beat, felt like it was written by AI, without any character. I can’t help but wonder if that would further frustrate the customer. Claude Opus 4.7 wrote the longest and perhaps most human of the three and provided its reasoning which is useful if you’re using AI as a collaborator and complete noise if you just wanted the email.
For pure send output: DeepSeek V4-Pro wins. The email is ready to go without editing. For collaboration: Claude Opus 4.7 wins. The email itself is strong and the notes are genuinely useful.
One issue: every model used em-dashes liberally. This matters if you care about your writing not reading like AI wrote it. Most people are fully aware that em-dashes are a sign of AI output. All three would need a quick edit before ending.
Test 2: drafting a contractor agreement clause
Most small business owners draft their own contracts because hiring a lawyer for every $5,000 freelance project doesn’t make financial sense. This test was designed to see how the models handle a real agreement drafting task with competing interests on both sides. Here’s the prompt:
Write me a 'scope of work and revisions' clause for a freelance contract. Context: I'm a marketing agency hiring a freelance designer for a $5,000 project: logo, brand guidelines, and 5 social media templates. I want to limit revisions to 3 rounds total to prevent scope creep, but I want it worded fairly so the freelancer doesn't feel pinned. Plain English, no legalese. Make it the kind of clause both sides would sign without arguing.
All three produced something usable, but the gap between them was the largest so far. DeepSeek V4-Pro wrote what feels like a real freelance contract written by someone who has been on both sides previously. It has clear definitions for each revision round, explicitly calls out what doesn’t count as a revision, and then includes a “quick note on the spirit” closing paragraph that humanizes the legal language. GPT-5.5 wrote something that feels generic and perhaps a little too tight. All the elements are there, but it reads like a template file from a random PDF you found online. Claude Opus 4.7 powered in with the most detailed agreement covering edge cases the other two didn’t (silent client approval, what counts as new scope vs revision, revision tracking). The level of detail is impressive but another fine example of Opus overthinking. Claude wrote a clause for a $50,000 engagement; DeepSeek wrote one for the $5,000 brief.
The clear winner this time: DeepSeek V4-Pro. The clause is the right length, right tone and gets the job done.
Test 3: handing a pricing objection
Almost every business owner runs into this conversation eventually. A potential client or customer asks for a discount. The request comes with a sympathetic story attached and you have to decide on the spot how to respond. If you get it wrong, you might lose the client or set a precedent you’ll regret. Here’s the prompt:
I charge 50 USD per hour for consulting. A new client just asked if I can do 35 USD per hour because she's a startup. What's the right answer? Don't give me a long lecture, just tell me what to say back.
All three models gave useful responses, but their approaches reveal how each one handles a question that has more than one answer. DeepSeek V4-Pro took the request and offered three different scripts depending on what the user actually wants. It doesn’t judge, and doesn’t give advice. The final piece of advice “don't justify, don't apologize, don't explain” felt like you were getting a response from your mentor instead of AI. GPT-5.5 picked one path, hold the rate but offer to scope down. Claude Opus 4.7 also picked one path, but added a “why it works” explanation.
This one is harder to call because the right answer depends on what the user wants. If you’ve already decided to pushback and just need the words, GPT-5.5 wins. If you haven’t decided, DeepSeek’s three-option menu is the most useful because it forces you to think about your stance “am I willing to bend or not?” and gives you a script for each.
I’d give this one to DeepSeek V4-Pro by a small margin.
Test 4: rewriting a weak headline
The final test is marketing. The headline I gave each model is the kind of thing AI itself would produce. I wanted to see whether each model could recognize it’s own slop and write something better. Here’s the prompt:
My homepage headline is currently: 'AI-Powered Solutions to Streamline Your Business Operations.' I think it's bad but I can't put my finger on why. Rewrite it three different ways and tell me which is best and why. Be honest about what's wrong with the original.
All three models pass the basic test of producing rewrites that were better than the original. But the depth of the critique and the quality of the alternatives varied a little more than I expected.
DeepSeek V4-Pro wrote the sharpest of critiques, naming the specific failures of the original, then produced three rewrites that each had a different positioning: pain-first, outcome-driven, and aspirational. GPT-5.5 provided the more structured response we’ve come to expert from its output: a bulleted list of what's wrong, three rewrites in a clean comparison table, then a pick with reasoning. The rewrites felt a little safe, none of them landed with the same sharpness as DeepSeek. Claude Opus 4.7 wrote the most thorough response of all three, going through what’s wrong with each word. Interestingly, it gives the only response that explicitly acknowledged it didn’t know what the product actually does. Claude’s rewrites were were positioned at three different angles, and it closed by asking the three questions a professional copywriter would ask before committing to any headline: who is this for? What is the measurable outcome? What is the proof?
This is the closest test of the four. The difference really comes down to the kind of help you actually need. I’m handing the victory to Claude Opus 4.7 because the depth of its consultancy.
What this means for your business
Four tests in, DeepSeek V4-Pro wins three of them. That wasn’t the article I expected to write going in. The narrative around DeepSeek has been “impressive value”. That really undersells what’s actually going on.
For the kind of work small business owners actually do (writing emails, drafting contracts, fixing marketing) DeepSeek V4-Pro is surprisingly the best option of the three. Not just the cheapest option, although it is by about 30x.
That doesn’t mean Claude and GPT lose every test. Claude has its powerful new design tool, GPT has the deepest tool integration ecosystem. DeepSeek is also a Chinese company, so you have to consider the privacy and regulatory implications.
I went into this article expecting to write a piece about how Opus 4.7 is a superior model, given I use it almost every day for my own projects. Instead I found that the cheapest model won, more often than not, on the work that actually matters.
The takeaway? DeepSeek is truly worth testing for at least a handful of tasks. And perhaps it is worth integrating it into your wider business workflows.

Sam Frost
Founder & Editor
Sam Frost is a UK-born entrepreneur based in Tampa, Florida, and the founder of Gulf Coast Brands. He has built, sold, and exited multiple businesses over the past decade, including a notable appearance on Dragons' Den (the British equivalent of Shark Tank). He writes about practical AI implementation for small and mid-sized businesses, drawing from hands-on operator experience.
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