Subject: Your head/face shape needs to be right for this to fit
The purple version has a shorter across the top of the head and shorter straps compared to the blue. I found (as a female - tried mens S, M and womens M and the woman's has the best length straps. The problem is though that the part that is supposed to go over the top of your head (at the back end of it) for me flaps behind my head (this is a problem actually with a lot of head gear regardless of the brand) and there is no way to move it forward (I have had to jury rig it since I like the memory foam mask that uses this mask). My head is a straight line (side view) forehead and chin. This appears to be designed more for a side view face where the lower part of your face is out further than your forehead. Be nice it they made the part that goes over the top of your head back/front adjustable (as well as being able to shorten it or lengthen it a bit). If it fits your head shape it works well when sleeping on your side, doesn't leave mark, and is light weight. If it doesn't fit your head shape creating a peice that goes over the top of your head and then velcroing it on (I cut apart old headgear and use their velcro end, cutting the length a bit longer than needed to reach the top of my head, had the pieces overlap the shut those with velcro) helps keep the mask where it needs to be and improves that fit.
Three stars for how it fits my face shape, 5 if it actually fits you correctly.