need your help on this one.....

The XA mono-blocs being Class A topology do get rather warm. I will not say hot as I have had tube amps in the past and those do kick out a lot of heat. I do not leave them on 24/7 instead turn them off when I retire for the evening. When I first got the amps I noticed the electric bill went up a bit maybe 5%. I know Pass does bias the X (AB topology) line higher into Class A than most manufacturers do so it will get warm. I have heard the same thing said about the 250 vs 350 but I have no experience with either amp so I can comment.  I would talk to Mark he is a straight up person and can give you a better idea of the sonic qualities of both. 

Chuck

will look forward to your response..........

I used to own a Plinius SA100 and now own a Pass X350.5

What I disliked most about the Plinius was that it took forever to sound its best once switched ON. The amp did not sound its best until being left ON for well over a week. Because of that, I just left it ON all the time. That was a big waste of electricity and heat generation. If you havn't tried already, those of you with a Plinius amp should try leaving it ON for a couple of weeks, then be amazed at how much better it sounds

The Pass X350.5 is a much better sounding amp overall and will sound its best after about 6 hours. Also, Pass amps are bomb proof reliable and made in the US. If you ever have an issue, just call them. Try that with Plinius!

Not to muddy the waters, but there are Clayton M300 monoblocks for sale on US Audio Mart that would also be worth a look.  Read reviews if you haven't seen them already.  Best of luck.

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.