Ray,
Having owned 2 of the 3 preamps (Insight and T8), they do have a slight difference in presentation. They are both great preamps but the T8 will obviously sway a tube lover. The phono section is awesome and the T8 can drive any amp. The Insight does share some of the T8's tube like qualities, without the fuss of tubes which I like and the Insight also has a great phono board. It's faster than the T8 IMHO, naturally one would assume this, and combined with a Insight power amp is a fantastic comination. The T8 I had drove my AVA 170EX extremely well and could produce a very nice soundstage. As far as the Ultra line goes, I have a lot of lint in my pockets right now, but someday I would be more than happy to have a 350 amp.
Wayner