Not an exact match, but I have literally just upgraded from Aerius' to Ascents this weekend. As far as I can gather, the Aeons pretty much superseeded the Ariuses, so I reckon the comparison won't be too far off.
The Ascents do everything that my Aeriuses did, just more so. Everything's higher, wider, deeper and sharper with the Ascents. The physical size difference alone means that the Ascents can project a broader soundstage that seems completely effortless. The crossover point is 150hz lower than the Aerius/Aeons (250hz as opposed to 400hz), because the bigger the panel, the greater its frequency response.
As much as anything else, this means that with the Ascents, sounds within that extended frequency range are better integrated with everything north of that region. Added to that, the woofer cone diameters are 2" bigger - and so they can go much lower.
That's not to say that there's anything wrong with the Aeriuses - far from it. They're great speakers - and to some degree, that's why it's difficult explaining why their bigger brothers are better. But it'll all make sense when you hear the Ascents.
As far as placement goes, you'd be surprised what you can achieve with room treatments. The Ascents have a switch on them so that the bass speaker can be attuned to the room (to a point - it lets you chose between a flat response and -3db), so that can help. But the brightness of the panels that might be overwhelming you in a small room with shiny walls.
I don't have the world's largest living space, and the Ascents are less than a foot from the back wall and two feet from the sides (with four foot between them). Seating is five feet from the speakers - like I say, not huge. But I have curtains behind the panels, and various other bits of furniture act as rudimentary acoustic treatments. No, the area isn't ideal, but the speakers still sound phenomenal.
Hope some of that helps. Oh, and if you can afford it, you won't regret moving up.
Neil
