Unsloth Studio [0] is what I recommend these days, open source alternative to the more widely known LM Studio, and also built by the people who make good quantizations of released models. With MTP support not merged in you should get 2x token generation speed with no accuracy difference. They also have MLX quants if you scroll down a bit, which is a format specifically for macOS' Metal GPU acceleration but that's not integrated into Unsloth Studio just yet.
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.
Curious if you tested llama.cpp and still found oMLX faster? I haven't tried the latter myself, might give it a go.
Oh yeah I did test various solutions and different settings and quants
Llama is about 1/3 slower on Apple Silicon.
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.