I auditioned for the BX2s (among others) not too long ago and they were my speakers of choice. I listened to them using a couple of different setups: the marantz 6005 with a project debut3 turntable, NAD C375BEE with a C-516BEE cd-player and the Rotel RCX-1500 with a build-in cd-player. All sounded great with the BX2s in my opinion but ...
... what I noticed isn't just that NAD puts more emphasis on bass than the others, but that there seems to be something going on that makes it sound messy in comparison to the other two, which sounded more ... clear, crisp and gentle I guess. Iron Maiden sounded messy and it wasn't capable to capture the playfull nature of Barbra Streisand whereas the Marantz could. I think NAD is great when you have things going on around the house, it definitely has a presence, but to those that really want to listen to their music and enjoy the nuances to it, I can't recommend the NAD. I don't know which if the two otherswould be better, but since the Rotel is a much more expensice machine the comparison might not be fair anyway.
Anyway, I came there for the speakers, not so much the amps, so I didn't pay much attention to the differences. The above is something I noticed though, regardless of paying attention to it. I hope that helped and maybe others can put more clearly into words what I experienced.