I've been using a Mirage Activa for a few years now, and lately it seems like the chin strap can't keep my mouth closed, thus causing leaks. I've gotten a full face mask (a Respironics Comfortfull2) and tried using it last night....It didn't work out so well... I took to the nasal mask on the first night, but this experience was fraught with problems...
First of all, for you full-face wearers: what's the trick? should I keep my mouth closed or open? it seems I wasn't drawing enough air and I was constantly yawning either way.
Second: It doesn't seem to give me a good seal unless I tighten it down. I've got a large, and I've got a big head so I don't know if going down to a medium will work. Even if I tighten it a fair amount, after a while, the leaks start coming.
I'll try it again tonight and see how I fare...will report back tomorrow.

