I have about 70 flights on my Boomerang with 5645's and never had a problem. I used them on my Panther and they seemed to be fine as well. I do not have an issue with using them on something in the 14-20 pound class that is not being "thrown" around alot. In contrast I have lost two planes in the past on both Futaba and JR servos, many years ago, so I feel just as comfortable with the Hitecs as I do with the other more favorable brands.
Tommy