I think you will find the Aerius (or Aerius i) much closer to their Aeon replacement than the Clarity. Despite its comparatively low price in the used market, the Aerius is a fantastic speaker and, with the appropriate electronics, can really be made to sing. I will probably get some flack for this, but I really wouldn't consider the Clarity to be a high performance loudspeaker in the same class as the Aerius or Aeon.
If you are looking at that Ascents and are really considering one of the medium-sized panel speakers and budget is really an issue, you may wish to consider a pair of SL-3's. They are about the same vintage as the Aerius and are the predecessor to the Ascents (uses the same panels). Given a choice, I'd take a pair of SL-3's with brand new replacement clear-spar panels over a random used Ascent. I just took a peak over at Audiogon and see there is a pair of SL-3's there for a mere $1000...a steal...while folks are asking more than twice that for an Ascent i. In terms of value, I think you'd do much better putting $1000 into an Aerius or SL-3 and putting $1500 into some upgraded electronics to feed them than dropping $2500 on the Ascents.
For a value shopper, you really can't beat the Aerius, SL-3, and Quest/Request vintage of speakers. The next generation Aeon, Ascent, Odyssey, and Prodigy speakers have really come down in price in the last year so their value has improved, but they haven't yet acheived the dirt cheap prices the mid-90's vintage speakers trade for.
Of course, this is just one guy's opinion...a guy with SL-3's who someday wants some Requests or Prodigies.