I have used the Nasal Aire I and Nasal Aire II, as well as the SNAPP masks. These are called nasal cannula mask as the prongs actually insert into the nostrils. I find that I could use them without much problem and did use them for a while.

My mask of choice at this point is actually a nasal pillow mask called the Headrest/Aura. The name keeps changing and am unsure what it is called presently. A nasal pillow mask doesn't actually insert into the nostrils but sit at the rim of the nares. They are actually the least obtrusive mask in most cases. I love this mask and although, many do not like it == I find it very comfortable.

Masks are very individual and are the hardest part of the therapy to find the one that suits your needs the best.