I am currently using the Pass X250.5 with a pair of Vandersteen Quatro's. As a former tube lover I was startled by the realism of the Pass, Quatro combination and sold my Quicksilver Monoblocks to buy the Pass. The dynamics and bass slam are just incredible and the midrange is as good as I had with the Quicksilvers. The system plays all types of music well. The Quicksilvers played small scale music a bit better than the Pass but as I listen to quite a bit of Classical and Rock, the Pass is a better match for my listening habits. I have heard the Pass with the 5a's at the Audio Connection and it works just as well with the 5A's. If you are anywhere near the Audio Connection in Verona, NJ you should go and listen to them and judge for yourself.
Good Luck with the hunt.
Good Luck with the hunt.