Well, it was good enough to convince me to buy the frame, but I found it quite hard to evaluate - I was in the middle of a 200km ride on my old fixed, which is quite lively (especially with the increased head tube angle), and the owner's Fixation was set up quite differently (bigger, higher bars) and running SS, and it was raining.
But I'm hopeful it'll turn out to be a bit more relaxed/comfortable, as I'd like to be able to do some longer rides on it, which I don't think I could do on the old frame.
Just waiting for the levers to arrive now, and it'll be ready to build up over Christmas...