I owned the 3A Signatures and recently sold them to fund the purchase of a used pair of Revel Ultima Studios. I've also listened to the Treo and Quatro CTs though.
Soundwise, I think you'll be happy with either.
The Vandys will need a lot more attention with respect to placement. The time aligned design means that the sweet spot will be fairly narrow. If I moved my head a few inches away from the sweet spot, the tonality changed markedly. What this means is it can drive you a little crazy dialing in the sound since small changes to either the speaker's position or your position can affect the sound.
The Revels were much easier to place in my listening space by comparison. The sweet spot is larger and if you move far away from it, the tonality doesn't change as much.
All the standard advice about speaker placement pretty much applies to the Revels. I recommend closely following the placement guide written in the 5A Carbon manual to get the most out of them.
Hope this helps!