I have them on models up to a 27% (43cc) Ultimate. Zero failures since I have been using them. I also like the removable pinned plastic hinges but CA is good enough for most applications. Check out MinnFlyer's tutorial. Drilling the pilot hole (I always do) and exposing the bare wood on either side of the slot appears to help a lot. I have destruction tested control surfaces on crashed models (can't blame a mid-air or a low roll ground strike on a hinge) and even after hard slams they outlast the surrounding balsa. I also use FRESH thin CA when it is time to hinge. Pin the center so you know you have equal amounts in both surfaces and drip 4 to 6 drops per side depending on size.

http://www.rcuniverse.com/magazine/a...?article_id=55