What is the best solid state amplifier you have ever heard?

I haven't heard that many and I tend to prefer tubes myself. With that caveat and the obvious fact I heard each of these with a significant amount of time in between and on completely different speakers/setups:

4) Sugden amps sounded really nice
3) Pass Labs XA30.5 (haven't heard the .8)
2) Pass Labs XA25
1) Nagra Classic Series sounded sublime