I've been umming and aaahing about getting a new airbrush. I have the Dinair one but I don't really rate either the brush or the formula of their water-based foundation. We used Airbase when I did my training at School of Makeup and I didn't really like it on myself, but that's mainly because I have quite bad skin so the tutor put several layers on and it looked very mask-like!
However, I've just recently discovered that there is a good alternative and that's Face Atelier. I signed up for their pro discount programme (which, incidentally, is pretty good - sign up online, free membership, 40% discount - you do have to order direct from them in Canada, but the shipping cost covers all your duties etc so nothing more to pay on receipt of the parcel - it's worth it if you're making a reasonable size order). When I went to order some shades of the Ultra Foundation (which is amazing, the best I've ever tried and I use it all the time now) I saw that they make a thinner that enables you to put it through an airbrush. It's a silicone based foundation so you would need to make sure that your gun was suitable for silicone based products, but the great thing is it's loads cheaper than Airbase (with discount) and it's a great product to use with a manual brush too so I don't have to buy separate airbrush products. You can also use the thinner as a mixing medium to make powder products into cremes/liquids (although I haven't even taken it out of the box yet so can't give a review of how effective it is - imagine it's good though, Face Atelier in general make fantastic quality products).
I haven't ordered an airbrush yet (the Dinair one won't be any good as it's for water based foundations) but I think I will, as everyone seems to want airbrush and there aren't that many offering it in my area. Just thought I'd share the tip for those thinking about doing airbrush.