De la Mancha appears to be a hobby project, but their new C64 SID emulator plugin, basic64 can be a serious toy. Functionally it is not a direct replica of the original thing, but the important parameters are implemented, with some extras. Sound-wise it has the special feeling of the old 8-bit age (though it has a 16-bit switch to make the sound better). Try it, it's free, but you can give some donation if you are satisfied.