I have owned the Ai500 about 8 months. It is a great integrated (even if you exclude the dac).
It is definitely well built. As Rapogee states, you do need it to warm up a bit. After running it for awhile, the unit does get get warm (around Bryston warm but not hot that you can fry an egg or burn yourself).
The amp has great control & authority and can handle my PMB MB1 by itself. Of course it has drawbacks when your try to power something this large but it has worked better than I have expected. It can control the woofers with ease and does provide some lushness for vocals with great neutrality. Maybe a tad bit of resolution loss b/c of the dirvers sucking the power out when playing 1812 but nevertheless still amazing!
Did I mention the fact that you can use it to bi-amp? I used the Ai500 to drive the 12" on the MB1 and Vitus for the tweet/mid. It was glorious!
I eventually (and regretably to this day) sold it as I did not have an extra setup for 2 systems so it would have been collecting dust in the corner of my room. I do miss it and I would not hesitate to buy it back if I need another amp. The guy who bought it from me has been VERY hapy with it driving his custom built ribbons and 2x8" Nuform Research bass drivers.
