I have not had a strap break, but I use neoprene slap straps. I have had the plastic insert that holds the lens into the frame come loose, causing the mask to flood uncontrollably, but that was apparently on in-water gear check, and I aborted the dive.
My mask came off on my first back roll entry, and when I got rolled in the surf at Laguna Beach, but not any other times.
My mask came off on my first back roll entry, and when I got rolled in the surf at Laguna Beach, but not any other times.