What are the weak points of Pass amps and pre-amps ?

@jetter 

Yeah... I under estimated the volume again.  Definitely hitting peaks over 100db+

Oh, on the subject of Pass Labs no question they underestimate power and the class A bias.  Bias meter barely moving.

87db 6ohm nominal load on the 5000's.  Don't HAVE to have big power, but man they respond.

Interesting comments in this thread.   I own big Class A amps and really like much about the sound but there can also be advantages to how Class AB amps present certain types of music.  Another thing I have found to matter is whether the output stage is driven by MOSFETs or bipolar transistors, with the MOSFETs usually IME offering a somewhat softer sound that is sometimes described as tube-like.  PASS and BAT use MOSFETs.  I tend to like amps with a bipolar output stage (like my Claytons), although I would like to hear the GamuT 250i monos and Pass' 260.8s both of which use MOSFETs.
I have heard good things about the sound of CODA amplifiers (bipolar output stage) but have been a bit confused as to why they have so many offerings.  IMO they would do better to establish a more concise line-up and stick with it - and offer more monoblock options.  The cosmetics seem a bit dated also but of course that is personal preference.

Where does Pass stand in comparison with Clayton and class AB Rowlands ? 

Tru-Fi sounds like another long-winded, hard pitched snake oil scam. I'm laughing.