Fair question. llmfit answers "will this model fit in my memory?" — it's a fit/size calculator, and a good one. whichllm answers a different question: "of the models that fit, which is actually best?" It pulls candidates, then ranks them by merged real benchmarks (LiveBench / Artificial Analysis / Aider / Arena ELO / Open LLM Leaderboard) with a recency penalty, so a newer 27B beats an older 32B even though both fit — on a 24GB card it puts Qwen3.6-27B above Qwen3-32B on benchmarks, not size.

If "biggest that fits" is the answer you want, llmfit is the simpler tool and Python won't matter to you. If you want "which fitting model is worth running," that ranking layer is the whole reason whichllm exists. Different jobs — I'd genuinely send fit-only users to llmfit.