'llama.cpp-based' generally seems like the norm.
Ollama is just really easy to set up & get going on MacOS. Integral support like this means one less thing to wire up or worry about when using a local LLM as a drop-in replacement for OpenAI's remote API. Ollama also has a model library[1] you can browse & easily retrieve models from.
Another project, Ollama-webui[2] is a nice webui/frontend for local LLM models in Ollama - it supports the latest LLaVA for multimodal image/prompt input, too.