jafant...
I've been running the Primare through a Classe pre and an Audio Research pre for about a week now. (I'm also coming into a BAT VK3i preamplifier pretty soon...) I'm leaning more toward the ARC preamplifier as that appears to be my "Thiel" amongst preamps - they've made every amp I've owned sound good. I purchased the BAT simply because I want to "tube" the front end.
I also picked up an excellent used pair of Von Schweikert VR5 HSE's only because the price was simply too good to pass up. Suffice it to state that the Thiel CS3.5's need not worry, although I enjoyed the VS in and of themselves. It's difficult to miss the mids and highs that the Thiels provide, and the VS's sounded veiled by comparison. I just sold the VS's.
Anyway, I'm liking the Primare. Even though Primare was somewhat vague as to the amp's 4ohm power rating, I find that it matches well with the Thiels. For approximately $2400 the Primare is a keeper. It doesn't emphasize the bass that my 3.5's do so well to any degree, which is a good thing, and those trademark mids and highs have not suffered, either. (That and my CJMF200...) There's a current ad on the Gon for a pair of CS5's that I would literally jump at - $1350! - if it weren't for the seller whom I had a previous poor experience with - his geographic location differs from the actual location he ships from, and I found that to be utter bs.
I am really looking forward to hearing how the BAT VK3i will complement my system. While the class d Primare doesn't over emphasize the highs, I think I'm finding the all solid state setup just a smidgen on the "bright" side. With the Classe preamp I found the upper end to be somewhat etchy, which seems to have settled down with the amp running for a few hours. The ARC didn't sound like that at all.
Anyway, I would recommend the Primare for anyone seeking a very decent amp at a very reasonable, IMHO, price.