Are Pass Labs amps probably the best ever you can buy ?

How anyone can say a certain Pass amp or any amp in general sounds thin without discussing speakers, preamps, sources or cables has no credibility. 

OP: your original question is silly at best i’m sorry to say. simply too many great choices to nominate one as best. have you heard Dartzeel, JRDG, Luxman, Vitus, Agostino, ML, Krell and on and on. That’s the fun of it; so many great options. When you throw “used” in the mix the door opens very wide. 

Steve McCormack’s new amps and preamp in my opinion are better.
www.smcaudio.com. 
Sanders sound Magtech.

LUXMAN IS ALSO GREAT

there are a lot of great amps.

like ice cream, too many flavors!

Not even close in my experience. 

Better value and better sounding than the Nakamichi PA7 [Pass designed] amp is the Usher R1.5 which is also a Nelson Pass design[a Threshold Stasis 200 copy].
The SIT 3 might be the best sounding of all the Nelson Pass designs but you would want to compare it with the Bakoon amplifiers which have a somewhat similar approach.The Bakoons are the best sounding  SS amps I have heard .Not quite Kondo Ongaku quality but getting there.