For whatever reason, I haven't been bothered by the OS update issues. The build quality hasn't been a problem either, except that the Stop and Play buttons' paint rubbed completely off and I had to replace them.
I'll definitely miss the pads and sliders, and I've gotten some way-out timbres with beatwide parameters, but at the end of the day, it's the overall sound for DRUMS that's not happening for me. It doesn't sound "bad", and I've programmed the hell out of it, but as a previous poster said, if it hasn't lit me up in a year and a half, it's time to move on.
Having six voices is a BIG deal for me. I've put way too much effort into voice allocation and planning ahead when making beats; I feel the limits constantly and it drives me nuts. I built the proper cables to take full advantage of the voice architecture and panning tricks, and it's just too much fiddling about. (It also took up damn near every input of my humble live-set mixer...)
The Tempest is super-powerful and that's why I bought it, but the sound just ain't doing it for me. It's an expensive lesson.