Which would you choose; Pass 250.8, arc 75SE or luxman m900u?

Current amp great soundstage but not exciting.
I had the Pass 250.5 (not .8) with an ARC REF5 SE and sold it for a REF 75 which I still own. The ARC combo is the best I've heard in my room and I had a few high-end units over the years to compare (Bryston, Classe, Simaudio, Luxman, Pass Labs, etc). Synergy is critical and of course this is facilitated when components are coming from the same brand. I was skeptical initially about the relatively small power number of the ARC amp (75W) but it sounds as powerful as 200W SS amps I had in my room and does have the quality of tubes without the 'disadvantages' (very neutral sound not warm). It's a Stereophile class A if that can help :-) I highly recommend this ARC amp and I've read many times that it sounds better than its bigger brothers in the ARC line (could not confirm that myself though).  
For the enlightened, perceived abuse of another member is usually the reason why posts are called to the attention of moderators for removal. 
I find nothing wrong with a dealer or manufacturer making a contribution to a thread if they feel it’s warranted. Even if such posts might be perceived as blatant self-promotion, it’s up to the OP to evaluate the content of each post, as well as the reasons why such info might be discounted. Most here are adults, so I’m confident that everyone can discern the content of each post for what it’s worth.
@guyl, ARC and others design their gear to work synergistically together. So I’m not surprised you enjoy your ARC combination.
@celander You are right. Impedance matching is particularly important and I've learned the hard way that mixing components that are great on paper but do not mix well does not provide the optimal setup. Of course, great combinations can be found even when components are not from the same company but like you said, gear coming from the same place is expected to sound great. It also help 'solve' the "what if" problem as what you get is what was intended in term of synergy and you are no longer wondering how the system would sound if you were to change a component in the chain. At least it worked for me as I do not have the same sense of urgency to make a move as before. If I wanted a different sound, it is very likely I would have to change the whole setup and go a different route. Anyway, some people may disagree with my statement but for me, finding a combination I like helped me focus more on listening to music than to my components/system :-)