I have an F-122 at home and an M-122 at work. I bolt-modded the M, but didn't use loctite. I've had to adjust the nuts two or three times when the F-24 key (mapped to 'power') would spontaneously fire. I was in the middle of doing something really important, it misfired and slept my computer. The F has always 'felt better', but I'm not super picky; After that incident, I had to pull out a Sun6pc to finish the day. I've been carrying the F-122 to work and back home each day since then. I managed to get one of the couple of F-122 at the listed price. It's more than I paid for the M-122, but a tenth of a kilobuck (shipped!) the reliability is worth it to me.