Yesterday running quantized models with CUDA was merged into candle:
huggingface/candle#1754
I haven't tested it yet, but right now it looks very unstable as its in a very early version. From the pull request it looks like it only works for Q4_0 quantization and has some bugs. But in the near future it may become as good as llama.cpp.
This would have some benefits. A native rust solution means no more build.rs, cmake, bindgen, no unsafe calls. Possibly the entire llm-chain-llama-sys could removed. The llama.cpp submodule could be removed, and people don't have to always modify the rust code when updating llama.cpp to get the new features. Also candle supports .safetensor files in addition to .gguf and the legacy .ggml.