did you have mk1 or mk2 cruds? they reckon on their website that the mk2's have been beefed up. with regards to losing chunks, the website just says, 'get in touch and we'll replace busted bits for free'.
I don't really have a complaint about them - I just don't like them much. The fixings held out OK- it was just bits of the guard itself that would get twanged off by stones now and then. Eventually it happened to the bit that you cable-tie under the brake, and I decided I couldn't be arsed to figure out a different way of fixing it.