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

I have a Pass X250.8 and it is wonderful in my system . 
I don't know where all this junk about heating a room comes from(I only wish). Yes they do run warm and you can feel some heat within a foot or so of the amp. Another great thing is the high bias class A, mine hardly ever leaves this mode.

I spent a weekend auditioning the X260.5 monoblocks and the glowing weak point in my set-up is their lack of speed and attack. Just sounded lazy when compared to Bryston cubed series monoblocks and Simaudio monoblocks. They were musical no doubt but sluggish.  

In my observation, those whose hearing is good enough - no need for golden ear - hear very similarly but they can verbalize it in a different and sometimes unclear ways and of course, sound preferences differ. Most of people around me prefer electrostatic speakers, as an example, and I don't. 
As for the Pass gear, it doesn't appear to be for me, regardless of certain fine qualities that it has. I wouldn't consider Bryston or Sim Audio either. I would skip all that and go straight to Gryphon or some Swiss gear for transistor sound. No idea about Italian or German electronics.

Pass amps very good not quite as good as WADIA but probably equal to McIntosh and krell. 

I have an Aleph 3 in storage now. It is sweet and delicate sounding but when I moved to a larger room it didn't work and maxed out below listening levels. It also runs warm and lacks bass punch and dynamics. It is transparent but speaks softly. I've never had high efficiency speakers but with the right speaker and a smaller room that amp could be magical.

My phono pre is an Aleph Ono that I've had for years. I find it very neutral sounding with good stage depth and imaging. It is also very quiet and has balanced outputs.

I've heard an XA200 and it was stunning. It had the same delicateness of my Aleph3 with way more dynamics.