-DJO
70cc twin V2
Basically plastic. I think superman is immune to them too...
I have had a few that held up to quite a bit of abuse but they are more prone to breaking from hangar rash than the mg's. I doubt you could break one in the air. Sometimes a bump to the control surface can cause them to strip. I had one on an aileron of my 48 edge for probably over 200 flights before it got stripped in the back seat of my car. According to some I was lucky to get that much mileage. The good news is you can put an mg gear set in them if it breaks. I did that with mine and it is still going strong.
I can't recommend using them because the mg's are a better option but if you do go that route put hb's on the ailerons and mg's on the tailfeathers.
Alright I'll see... probably go with those for the ailerons like you suggested, then the MGs on the rudder/elevator.
We'll see if I buy the 48 first though...
Dan