River,
One reason I kept the Joule was that I liked the sound a lot - especially into my primary speakers at that time, Verity Parsifal Encores. IMHO, the AI was a better match for my other main speakers, Merlin VSMs. Both of the above observations subject to choice of power amplifier.
The VSMs ended up in a second system which - as a practical matter - required a remote controlled preamp, so the AI was sold off.
Therefore, I would't read too much into my choice of which pre to keep.
I think it's really a matter of features, ergonomics, system matching, brand confidence (good to hear that AI seems to be getting better) and personal "sonic" preference in this one.
Marty