Sillyme, it's so good to read that you've found a mask that works well for you! I know that it's been a struggle.
I just wanted to thank you because your thread has helped me! I've used CPAP for over a year now. I have tried MANY masks during that time -- about 15. I have a thin, angular face (plenty of padding elsewhere!), and full-face masks don't seal well for me. I finally settled on nasal pillows masks and I usually use the AEIOMed Headrest, which does work well for me.
After reading of your experience with the FP 431, I dragged mine out of the Mask Graveyard (a large under-bed box) last night to give it another go. When I tried that mask once or twice before, I didn't make it through the night due to constant leaking. Well, this time it worked, with zero leak rate and great results numbers too. And the mask is SOOO quiet! I can't say it was 100% comfortable for me. I did have to tighten the top straps very tight in order to prevent leaking around the eyes, but this is the first full-face mask that shows promise for me. I'll keep working with it to see if there's any way I can wear it looser. Just goes to show, "if at first you don't succeed, try try again."