I would also go for the Ascent!
When I purchased my Ascent-i's, I actually auditioned the Ascent (non-i) alongside the Aeon-i. While both speakers are excellent, I found while listening to a Beethoven violin sonata that on descending passages in the piano, I could hear a chestiness develop in the lower midrange of Aeon-i that was not present in the Ascent. Maybe this is caused by the x-over occurring at 500Hz (just above the A above middle C) on the Aeon, whereas the x-over is at 250Hz (just below middle C) on the Ascent. I suspect that the 250Hz x-over is tonally more benign, as it occurs at a less crucial point in the musical spectrum. Then again, I could be full of you-know-what, and the electronics could simply have favoured the Ascent in this audition.
When it comes to Ascent vs Ascent-i; well I purchased Ascents, but they were damaged upon arrival, so I had them for a week until Ascent-i's arrived as their replacement. Between the two, I would say that the only really audible difference was in the bass, where the Ascent-i is noticeably punchier (with rock music) and faster, whereas the Ascent might reveal more timbre and texture with instruments like 'cello. I would consider the Ascent and Ascent-i as interchangeable - differences in sound, yes, but equally enjoyable. Swapping out the parts to turn an Ascent into an Ascent-i will get you a slightly different sound, but I would not consider it a sonic upgrade.
Whichever speaker you end up with, I bet you will love them - they are both great speakers.