I truly do not feel that this can be answered validly. An amplifier's performance is, to a great extent, dependent on component synergy. All too frequently, people get to audition various pieces of equipment in a dealer's store who will frequently carry only limited brands of cables and other components. Merely inserting different makes of amplifier into an otherwise identical system, does not necessarily imply the comparison has validity. The amplifier (under audition) may require different components to make it really 'shine' (these components are frequently unavailable in the dealer's store, in my experience). Of course, there are other issues, such as type of music for which the system is intended. These variables are not mentioned above.
Best solid-state amp made anywhere
I'd like to open up this "best of" to include amps from New Zealand, Canada, France, England, Germany and (my personal favorite) Italy, as well as whoever else I've left out (no extraterrestrial amps, please). I have spent some time with the most amazing solid state amp - made by Aloia of Italy and uses an inductive (!) power supply. These amps have a naturalness and ease I haven't previously encountered in solid state, not even Pass or Claytons. Have you noticed that the Italians make superb audio equipment? In this country, audio engineering is to engineering as podiatry is to medicine. It just doesn't typically draw the cream of the crop. In Italy music matters far more, and audio equpiment is designed by people who will make an opera singer sing her part over if they aren't satisfied with her performance. Well enough sociology - what's your vote for best solid state amp?