Just built up a Jamis Exile SingleSpeed.
So far my review is that it's awesome. I had heard that there were problems with the clickit lockout but that Manitou fixed them halfway through the production. Mine is fine so far. I've never ridden with suspension, and I've never had disc brakes (much less hydraulic). I've quickly become a fan. My other mtb is an aluminum frame (XACD) so I'm loving the reynolds 653 on this too.
I'm not getting rid of the full rigid or the fixies anytime soon, but for a while I think I'm going to try to focus on getting on the dirt.