Muse Spark (Meta) vs StepFun Step 3.5 Flash
Which one should you pick? Here's the full breakdown.
Muse Spark (Meta)
Meta's first model from its Superintelligence Lab -- natively multimodal with Contemplating mode for multi-agent reasoning
StepFun Step 3.5 Flash
StepFun's (China) agent-focused open-weight model -- Step 3.5 Flash launched 2026-02-01. 196B sparse MoE, ~11B active. Benchmarks slightly ahead of DeepSeek V3.2 at over 3x smaller total size. Step 3 (321B / 38B active, Apache 2.0) and Step3-VL-10B multimodal also in the family
| Category | Muse Spark (Meta) | StepFun Step 3.5 Flash |
|---|---|---|
| Ease of Use | 9.0 | 6.0 |
| Output Quality | 8.0 | 8.0 |
| Value | 10.0 | 9.0 |
| Features | 8.0 | 8.0 |
| Overall | 8.8 | 7.8 |
Pricing Comparison
| Feature | Muse Spark (Meta) | StepFun Step 3.5 Flash |
|---|---|---|
| Free Tier | Yes | Yes |
| Starting Price | $0 | $0 |
Benchmark Head-to-Head
Muse Spark benchmarks — StepFun Step 3.5 Flash has no published benchmarks
| Benchmark | Description | Score |
|---|---|---|
| MMLU | Knowledge across 57 subjects | 89% |
| GPQA Diamond | Graduate-level science questions | 86% |
| HumanEval | Python code generation | 91% |
| Humanity's Last Exam | Frontier difficulty questions | 58% |
Which Should You Pick?
Pick Muse Spark (Meta) if...
- ✓Easier to use (9 vs 6)
- ✓Better value for money (10/10)
Anyone who wants frontier-level AI for free. If you use Meta's apps (Facebook, Instagram, WhatsApp) already, Muse Spark is the most accessible high-quality LLM with zero cost.
Visit Muse Spark (Meta)Pick StepFun Step 3.5 Flash if...
Teams building agent systems on Chinese open-weight foundations who want something other than DeepSeek or Qwen, especially if agentic tool-use is the primary workload. Also good for Chinese-market products where StepFun's domestic tuning advantages matter. And for anyone looking to add diversity to their open-weight evaluation matrix beyond the top-3 Chinese labs.
Visit StepFun Step 3.5 FlashOur Verdict
Muse Spark (Meta) is the clear winner here with 8.8/10 vs 7.8/10. StepFun Step 3.5 Flash isn't bad, but Muse Spark (Meta) outperforms it across the board. Pick StepFun Step 3.5 Flash only if teams building agent systems on chinese open-weight foundations who want something other than deepseek or qwen, especially if agentic tool-use is the primary workload.