Model choice guide
GPT-5.5 vs Opus 4.7 vs DeepSeek V4: best model by task and budget
Pick GPT-5.5, Opus 4.7, or DeepSeek V4 by workload: coding-agent speed, hard planning, open-model cost, multimodal work, and live provider routes.
Shi Xiang 'Best Ideas' community discussion · 新一轮模型发布：当智能进入月更时代
This guide synthesizes perspectives from a Chinese Shi Xiang 'Best Ideas' discussion on recent GPT-5.5, Opus 4.7, and DeepSeek V4 releases. It is an original whichllm interpretation for builders, not a translation or republication.
Quick answer
Do not choose GPT-5.5, Opus 4.7, or DeepSeek V4 by a single benchmark. Choose the model whose failure mode matches the workload: speed, planning depth, open-model cost, or multimodal understanding.
- Use GPT-5.5 when coding-agent speed, tool loops, and quick test-fix cycles matter more than maximum deliberation.
- Use Opus 4.7 when hard planning, long task chains, visual reasoning, or expensive mistakes require deeper first-pass thinking.
- Use DeepSeek V4 when open-model economics, provider choice, and cost-sensitive coding throughput matter more than closed-model polish.
- Check live routes before buying because provider pricing, context windows, and model IDs can differ across OpenRouter, Bedrock, Vercel, GitHub, and direct routes.
Best first model by workload
| Workload | First model to test | What to verify live |
|---|---|---|
| Fast coding-agent loops | GPT-5.5 | Latency, tool-call stability, GitHub/Vercel/OpenRouter route fit, and how quickly the model recovers after failing tests. |
| Long-horizon implementation | Opus 4.7 | Plan quality, context handling, multimodal understanding, and whether fewer retries offset the higher route cost. |
| Cost-sensitive agentic coding | DeepSeek V4 | OpenRouter/direct/provider price, output shape stability, and whether cheaper calls still preserve the workflow. |
| Product planning or architecture | Opus 4.7 | Depth of tradeoff analysis and whether it catches hidden constraints before code is written. |
| High-volume extraction or refactors | DeepSeek V4 | Total batch cost, retry rate, context limit, and whether the provider route supports your throughput needs. |
| Rapid prototype shipping | GPT-5.5 | End-to-end cycle time across prompt, code, test, patch, and deploy rather than only token price. |
The real comparison is workflow fit
The old model directory question was simple: which model has the biggest benchmark number? That question is no longer enough. New frontier models arrive with different tool-use habits, serving routes, pricing shapes, latency profiles, and failure modes.
That is why a stronger model can still be the wrong choice for a specific team. A coding agent loop may benefit more from GPT-5.5 speed than from deeper deliberation. A high-risk planning task may benefit more from Opus 4.7 reducing retries. A high-volume workflow may be better served by DeepSeek V4 if its open-model cost keeps the loop affordable.
Model notes
GPT-5.5
Best first test when engineering speed is the bottleneck. For coding agents, lower latency and stable run-patch-test loops can matter more than winning every hard reasoning prompt.
Check OpenRouter GPT-5.5 pricingOpus 4.7
Best first test when the task has many dependent steps, visual context, or a high cost of a bad initial plan. The buying question is whether fewer retries justify the route.
Check Bedrock Claude Opus 4.7DeepSeek V4
Best first test when open-model economics and provider flexibility matter. Compare DeepSeek V4 Pro and Flash routes before assuming one provider has the cheapest useful path.
Check OpenRouter DeepSeek V4 ProBudget changes the answer
Model choice is a budget decision as much as a capability decision. Agentic workflows amplify token price because one user action can trigger planning, tool calls, logs, retries, and context compression. A model that looks best on one prompt can become expensive when it runs all day inside an automation loop.
For production work, test the same prompt pack across one GPT-5.5 route, one Opus 4.7 route, and one DeepSeek V4 route. Track total cost, latency, retry count, answer shape, and whether the provider route exposes the model ID, context window, and billing detail you need.
Compare live routes on whichllm
Use this guide to choose the first model to test, then check current context windows, model IDs, provider routes, capabilities, and token pricing before wiring GPT-5.5, Opus 4.7, or DeepSeek V4 into a workflow.