Yeah I have an LH1000 here and it's a great amp. I need an easy to move amp for a second room, a small amp as well. I could go silly and get the $250 TC 500 but I don't think ultimately that would make me happy. If you already have the Mesa I wouldn't worry too much about another amp! I think the Quilter is all about simplicity though, kind of opposite the Mesa style. Even simpler than a Mark Bass, the other ones I was looking at.
It really is kind of funny though. If Mr. Quilter had simply used TRS for the line in, and XLR for the line out, it would have made everyone so much happier. Don't even worry about the headphone amp feature. Maybe the 803 will have these features someday, if there ever is one. I guess there is no "perfect" gear even the 99% great stuff is still 1% wild at heart, you have to live with some of it I guess.