Hi Marlena - I have the Copic AirBrush system and the compressor, and I use it for backgrounds and to color ribbon and bling and that sort of thing. I bought the AirBrush parts at JoAnn's, with a 405 off Promo, and later added my compressor which I bought at Harbor Freight. I was given the link from one of the girls and this compressor works great and is far less then the one they sell on the Copic sites!
I do like it, but probably do NOT use it as often as I should. Looking at how fabuous your cards are -- (the slideshow is going by while I am typing this), I can see that you have already mastered your own way to create fantastic backgrounds!
For the price I paid, I'm still very happy and would likely buy it again! I know I could use it more, but like everything, it's a matter of time. I have my compressor right on my desk and grab it often, simply for quick edging!!