I've been trying a UMFF for less than a week now and I'm completely unimpressed. I normally use a Mirage Activa with a Respironics chinstrap. I see leak rates higher than I'd like but I almost NEVER feel them escaping around the sides of the mask. If I do I adjust the mask straps some, usually just a tad tighter.
Last night I woke up with the UMFF off. This has happened before with the Activa so that alone isn't odd although way way too soon for something I'm trying out for the sole purpose of being able to breath WHEN MY NOSE IS CLOGGED by allergies.
If my nose isn't clogged, I liked the freedom the Activa gives me to sleep on either side or my back. (When I'm on my side often I'm half on my stomach on a pillow or blanket)
And yet each time I try to use the UMFF the only way I can use it is laying flat on my back only. Even then it leaks. Unless I TIGHTEN that thing down so tight it's ridiculous. And I went to sleep like THAT last night only to wake up feeling terrible with the mask off.
I like the idea of not wearing a strap and breathing through my nose 90% of the time and the mask catching 10% or whatever of loose air through my mouth but laying there flat on my back and actually feeling it leak massively in different spots is a completely new feeling for me after 2 years on cpap. Perhaps it's the shape of my face.
Thank god I bought the return insurance. I've decided to box this thing up with it's return label and send it back to cpap.com and probably get another mirage activa, although i'm open to one of the masks that are more popular. The Activa is only purchased by less than 5% of nasal mask buyers while others are 40%. Still, it's hard to look "active cell" technology in the mouth...because I had no idea how well that works....until trying the UMFF.