I have a medium sized hamster ball and a little girl suggie who L-O-V-E-S it. If you are afraid of the glider getting out, put a piece of tape on it so they can't pop it off. I have never had a problem with it. Really, it is the only way that my suggie gets around the house (i have two cats). Yes, you do have to clean it out, but common...when aren't you cleaning up the poop and pee of a sugar glider?? Just time it right. Let them go before you stick them in there, and all is fine. I can see where the air holes would be an issue, but if you watch after your glider I would guess you would be able to catch it before something extreme happens.
so yeah. mine loves it, never had a problem with it...but I would still keep a watchful eye on the glider when they are in it.