need your help on this one.....

Watts are over-rated in my opinion, unless you have an extremely large room, highly inefficient speakers and like to play LOUD.  Current, quality of parts, design and build quality should play a larger role in your decision process.    

Pass and Plinius are both very reputable.  

I believe the SA 301 is class AB... so I'd recommend the SA-102 or SA 250 which is biased for Class A and has a toggle switch to run in AB.. but I strongly preferred running the SA-102 in class A when I owned one about a decade ago.

Pass has an excellent reputation, stronger name recognition and may have better resale value.

I agree with poster "seasoned" that Plinius have to be left on all of the time to sound their best.  Plinius SA 102 was the best ss amp I've owned, but I'm a tube guy and my exposure to ss amps is limited.

Based upon feedback from others on this chain and your preferences, it sounds like a Pass X250 or 350 series amp is the most sensible path forward for you.

Soix... yes, I left my Plinius on 24/7 and toggled over to the more energy efficient class AB when not listening, then back over to class A for listening sessions.  I think most ss amps and ss audio equipment in general sounds best when left on 24/7.

No, as long as you left it on 24/7 in A/B mode, the warm-up once you toggle over to class A only took 20 minutes or so.