Well, the T7 is certainly quieter than the AI, put your ear up to the speaker and you can hardly tell the system is powered on. In most areas the AI and the T7 are more alike than similar, but I would give the edge to the T7 overall because the highs are more extended and clear, the bass is deeper and tighter, and there is very little low level compression. I've noticed that "many" pieces of high end audio gear have a bit of low level compression, where the soft notes or quiet parts are boosted a little bit, giving the impression of having more "detail". With the T7, the low level stuff is still there, but it's not pushed out at you as much. As a consequence, where there is a quiet part to the music, the T7 lets it play as truly quiet. I am suprised at how much just this one area makes listening to music more enjoyable.
Also, the T7 has a stepped volume control, but it's nowhere near as big a jump in volume between settings. That was my main complaint against the AI (besides the fact that the AI was susceptible to the RFI problem I have here). The reviews all say that the AI was a heck of a preamp, and I agree, it really is. That said, I do like the T7 just a little better.