Verdict
Built from the measurements below
- Accuracy is too close to call: Claude Haiku 5.5 scored 68.8% and DeepSeek V4 Flash Vision Exp 71.2% on the same 80 questions, a gap within what chance alone could produce.
- Claude Haiku 5.5 is 2.2× cheaper per question as billed ($0.00048 vs $0.0011), reasoning tokens included.
- Claude Haiku 5.5 generates text 1.1× faster: 192 tokens per second against 170.
Which should you choose?
Choose Claude Haiku 5.5 for the lower cost per correct answer ($0.0007 against $0.0015), faster streaming and more hosts to choose from on OpenRouter (5 against 3). Choose DeepSeek V4 Flash Vision Exp for open weights you can run yourself.
Accuracy gap -2.5 points (z = -0.35). We call a winner only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.