The four models in the new Brooks Pure Project shoe line seemed interesting when I had a chance to check them out in Switzerland last July. Unfortunately they were not allowed to sell any of them yet.
I'd surely be interested in trying Pure Flow for short training and racing, perhaps even for marathons. Also Pure Grit might be useful. The other two I'm not that interested in.
I'm afraid the Pures might be too minimal for ultras, unless you can run like Krupicka - I certainly can't. We'll see when they become available in Europe.