pyvips (the libvips Python binding) is quite a bit better than pillow-simd --- 3x faster, 10x less memory use, same quality. On this benchmark at least:

https://github.com/libvips/libvips/wiki/Speed-and-memory-use

I'm the libvips author, I should have said, so I'm not very neutral. But at least on that test it's usefully quicker and less memory hungry.