I'm on my 2nd pair now, I love them, I'd go a full size bigger to anyone ordering though, they do run a little small I think, my 12s are a lot nicer than my previous 11.5s.
My only complaint about them really is that the lightweight mesh they use really doesn't last very long, but mine are a race shoe, so it's not an issue for me, but if you were going to use them for serious miles I'd imagine durability might be an issue