Animated Blitzwing. Times Transformed: 0... That's right, still brand new in package, at a Walmart, his head/nosecone was already popped off the socket. Didn't stop me from buying him though. I did get his head back on with no issues, and it doesn't pop off. However, the rotating mechanism for his faces doesn't move too well.
I don't have any that just fall apart, but my Universe Galvatron is pretty loose and flimsy. RoTF Scalpel isn't really loose, but really fragile with those little spider legs. I pop those off anytime I touch the thing.
Animated Swindle, he was perfect at first, but then all of a sudden, his arms broke off and now I can't fix them.
Uh, didn't I ask this question a week ago? http://www.tfw2005.com/boards/transformers-toy-discussion/301296-transformers-durability.html But to answer your question. I just received my KO Sunstreaker last week, only transformed him 3-4 times and already starting to see a stress mark basically where his arm-pit would be. It's the thin plastic behind his arm as you fold it backwards to lock into car mode. Seems like his joints are very tight. So I doubt he will stand much transformation.
Ugh, lining up Smokescreen's legs in car mode has been known to make my blood pressure skyrocket. Silverstreak isn't a problem, strangely enough.
alternity convoys back of his legs. it all cheap clear plastic it will snap with very little pressure. but i fixed mine.