FWIW,
I have used PEAK VSTwith OS9.x for 4 years with very little problems and excellent customer support. I still haven't upgraded to OSX for a variety of reasons, but it sounds as if I will have to change programs when I do.
There are a few strange things I guess I have gotten used to, but is has down all I needed it for. that said, I do not record to laptop and do not store 24/96 files.