I used the SGC's alot and never broke one. I'm careful to just sorta roll the collette barrels into those clips so that the splines gently part slowly and only enough to allow the mics to slide in...the key is to use the angles on the back of the mic and kinda roll the mic body as you're sliding the mic in. I can definitely see where breakage could be an issue, but I haven't had any problems using this technique.
BTW, Im with you hi and low. I like the SGC clips although SGCM would be even better. They hold the mics with authority and precision and since they're gripping the back grommet, screens slide on without any obstruction.