I'm not sure what your tastes in Bass are...
but I went and auditioned both the Summit and Vantage at an Audio Advice showroom in Boca Raton, FL. I went with a close friend and my fiancee. My fiancee has always been of the mindset "I can't tell the difference anyway, so why would I pay for a difference?" I hoped to change her mindset with a pair of Logans (so she'll let me buy them!)
The Summits were the only speakers in their room, with a Krell Integrated amp and SACD Player. The Vantages were set up in a room full of different equipment (which also meant it was a bigger room) I believe a high end Denon was powering the Vantages.
In the relatively small room the vantages were in, they sounded wonderful. Very fast and clean. I was very impressed. The bass was fast, and not overwhelming. The fiancee, in an A/B comparison with some equally priced box speakers (I'm don't remember the brand...Polk I think, but don't hold me to that) could tell a big difference as well, and greatly preferred the Logans.
Then we listened to the summits. In the smaller room. Too much Bass. The sound was actually much less focused. I didn't want to try to show the salesman up by offering to adjust the toe in and bass controls...plus, I don't think it would have helped a ton in a 10x10 room.
So, I got buy in from the fiancee on the Vantages...and convinced her (as I firmly believe) that the issue with the Summits was the tiny room they were in...so when we upgrade to a bigger house (we're having a small one built that will be done early next year....the Vantages will go in that) we can give the Summits (or whatever is available then) a shot.
So, a win for me...but a loss for Audio Advice, for having their premier speaker set up in a tiny tiny room.
Enough of me rambling. Unless you're a major bass head, the Summits output a LARGE amount of bass that should be able to fill most spaces quite easily. If you ARE a bass head, give the descent a try. I was VERY impressed by the speed and power of the bass in that baby. I would really try to find someone else in your area who has some Summits, or next time you travel out of state, make a point to visit someone (or some showroom) that has them...for a second opinion.
Unless you LOVE seismic bass, the Summits should do it for you...so I'd investigate other factors.
sorry for the temporary thread hijacking
I tend to ramble