Dagery, that is one hellaciously fine amp! I had the pleasure of doing somewhere around 3 hours of serious seat-time with one several months ago, paired with Martin Logan Motion 60xti and GoldenEar Triton 2+.
Why stand-mounters? Small sound room? Do you have a sub in the mix?
Having not heard either of your two contenders, I can't offer anything in the way of solid advice. Speakers are too personal a choice anyway. However, I can say I've done about 1.5 hours of serious seat time with the Aerial Acoustics 6T, paired with a MAC tube stack (i.e. MC275) recently and, this month, the B&W 702s2 paired with a Denon and, then, a Pioneer 100 watt AVR. The Aerial 6t & MAC stack matchup was absolutely stupendous! That is a truly outstanding speaker! Unfortunately, my amp (Mcintosh MA5200) just didn't have a big enough power supply to do them justice. The B&W matchup with those two different AVRs were nice, too.
Going on specs alone with your two contenders in mind, I suspect the reason(s) you found the B&W leaning toward brightness is because they are primarily an 8 ohm nominal load design and your amp is a real powerhouse, very conservatively rated at 100 watts (likely more like130 to 150, I'd say). Those Aerial are a 4 ohm design. They need more juice. Specs, especially with speakers, are always to be taken with huge grains of salt! However, seems like the Aerial will perform a little better in low bass and likely will be more accurate & detailed than the B&W. Maybe this and the 4 ohm design are why you found them a bit more "mellow".
If you don't have any dealers within 500 miles, how did you hear them? Home demos? Friends? Did you listen under relatively controlled conditions (e.g. amp like yours; room like yours; equipment like yours; etc.)? I'm all but certain your amp has more than enough power & current to rock the B&W and would wager the Arial, as well, but it's always a good idea to do some controlled critical listening, first, if possible. Always trust your ears!
