I have researched for quite a bit and so far the fastest runtime is the oMLX one. But there's a caveat: ttft on MLX on M4 Pro is enormous. On M5 Pro it has been greatly sped up.

I tried Unsloth Studio recently and was disappointed - in particular the downloading functionality is half-baked and didn’t cope with resuming downloads. As it seemed to just be a simple wrapper over llama.cpp, I found that huggingface hub, llama.cpp, and a couple of simple scripts actually offered better functionality once it was set up.