Not counting the many a dozen I have in my vault at work (or have used at work period), because some would say if running that many you are bound to see more failures, and going off just the ones that I have personally paid for...no! They didn't even "take a beating" the just failed. Failures to hold zero, failures to track were the main issues. I sold them for a reason. These were the variable power 30mm versions, the "newer model" MK4 (and higher models) seem to be doing better. The originals (M3 Ultra/fixed 10 power) I don't remember having many issues with. I still use them, just because I don't have to pay out of my own pocket. At least their customer service is great, they have even overnighted me a loaner. Someone mentioned IOR, will never go down that road again. Had a few failures with them as well. Getting them "fixed"/replace must have been a logistical nightmare, took many months each time.mk4 won't take a beating?