I'd be interested to know how you get on Pete - are these the XT Ultra 260 mk II? They haven't been out long and I'm intrigued to know if they have improved on the mk I which, as was mentioned earlier, is a rehash of the original X-Claw 275 (the sole is identical btw). I've got through about four pairs of the X-Claws and am on my 5th pair of Ultra 260s, but that doesn't really tell the story of what I think is a flawed shoe - the 260 mk I has a sloppy and loose heel that's cut very high, awful for contouring. I buy them because the accommodate my fat feet and the lightweight orthotic I'm obliged to wear, but am hoping the mk II has addressed these issues.