Hmmmmmmm, hard to tell since the MP88 are less popular but I think that the MP series overall are very brttle. I read alot about MP100's breaking mainly due to clashes, but some were strung at pretty high tensions, MP99 cracking seems very common, and I've had a friend have 2 MP77s crack on him.. Also, it depends on how you're determine how durable it is. Are you talking about withstanding tension or like clashes?
mp88 and mp99 are suppose to have thinner frames than the other mp's so maybe in that sense they are more brittle. The previous point is well made that mp100 seem more brittle because more ppl have them and therefore you see more of them breaking than mp88. as far as strength of the racquet as far as tension withstanding ability, mp100 and mp99 should be better than mp88 just because they are heavier and stronger racquets than the mp88. As far as clashes, if you hit two racquets hard enough together, something is bound to break anyway so just try to avoid that as much as you can.
