I've got a real Iwata Airbrush and the Letraset Marker Airbrush as well, but the art store I work at discontinued the Promarkers which I needed for the Letraset Airbrush. So it seemed like it was time to get the Copic one.
I made sure to get the one that had the adaptor can, because I already had a compressor. I highly recommend that if you are going to use this even a moderate amount, get a compressor.
No matter how good the airbrush is, or the canned air is it just won't be as consistent as having the compressor.
There are of course, pro's and con's of both. The compressor is a one time cost, though it can be quite a cost, but you only have to buy it once, it's also not as portable as cans of air. the Cans of air are definitely less expensive, but in the end you pay more over a longer amount of time.
Think of it:
There are 2 air cans you can get for Copic. The D60 for $13.40 you get