In reply to petemacpherson: Sorry it's a bit late pete, and I appreciate you were being sarcastic but I'll answer the question as well as I can, although I doubt my experiences will be justify the apparently audacious comment I made earlier.
Like the person that posted below you, I've only had my mantas just over a year and already the sole is worn down to an extent where I wouldn't chance my feet in them.
Also if the plastic cover comes out before you want to wear them it fills with crap meaning it's almost imposible to get the crampons on.
But if the plastic cover doesn't fall out then, in winter, with gloves on, how do you suppose to get the cover out? the only way I have thought of was to use your crampon itself, which could lead to a nasty injury. The plastic bits are hard enough to get out in the warm and dry with perfect visibility and no gloves on. I can only imagine how hard it must be in a winter blizzard, wearing gloves.
But my main issue with the idea, is that there is absoloutly nothing wrong with the traditional step-in crampon, infact, unless you walk around with the plastic cover out of your boot, I would even go as far as saying that I think it's probably quicker to use the more tradition ones too. Plus you don't have to rely on buying a new set of boots every year and a half.
So that, in my finite wisdom, is what is wrong with the GSB idea crampon.
Rich