We had a plane go through a metal roof it was a .60 size. We had 6 servos on board4 were 322 HiTec and the other 2 was 3004. Both of the 3004 had damaged gears the HiTec gears were not damaged. This made a believer out of me. I use HiTec HS-625MG and HS-645MG and have been trouble free. Not to say the other ones aren't OK because I have several Futaba servos that I have not had any problems with other than these 2.