I have experience with the Airfit F20. My main problem with it is it tends to really dig into the bridge of my nose to the point of leaving a pretty good indentation and soreness. Putting a band-aid across the bridge of my nose helps with that. I've tried the memory foam one, but you can't wash it. I'm used to washing my mask every day with mild dish soap and water, and the memory foam can't get wet. I'm not sure I can wear a mask I can't wash. I think there are some wipes you can use on it, though, but that doesn't seem quite the same to me.
I'm currently using an Airfit F10, but I just saw something today indicating that mask is being discontinued. I may have to make peace with the F20.
I, too, have a hard time finding a mask that works. When I go to sleep, my face muscles relax, and the mask fits totally different than when I try it on. I tend to get big leaks that way.