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

Jetter, I own an XA25. It’s cheap in that it punchers wY over the specs and is brilliant.  I also own their pre XP-22.  Have had XP10 as well. Very good equipment.  There is nothing bad here.  I came from mostly Reference level CJ TUBE equipment.  

Well thanks medwardo and jahatl, you have both convinced me that the XA25 is not worth the investment.  Well that's totally not true, and in time I feel I will be purchasing one, but not for a little while yet.  Enjoy the Pass, and its all fun.  
George

Since you are interested in the difference between XA and X, call Kent English at Pass.  5308785350

I have the XP-12 which can turn on the XA60.8. The Ayre preamp couldn't. I needed that functionality.

Wayne, the designer of the preamps told me that the XP-10 cannot turn on the XA60.8. 

The combo is good to my untrained ears.

 If you are worried about the price of Pass amps and happen to have efficient speakers, try the First Watt line. Wonderful amps that won't break your bank.

I have not heard all of Pass Labs amps, but from recollection of a few I did owned it’s good but not great.
I had the X350, X350.5, XA100.5, XA160.5, XA160.8, compares to MSB M202, M203, Lamm M2.2 and ARC REF250 and even Bryston 28B3, one would wonders what the hypes was all about.
As you can see, I did fall for the hypes with owning 5 different Pass models.
Not bashing on Pass, I’m sure the XS is a must for class A enthusiast, including myself.