I disagree...I used Badgers and Paasche brushes for nearly 20 years before I switched to an Iwata, and the difference is very obvious.
Let's face it, you get what you pay for. I find the Iwatas to be better engineered, higher quality castings and machined parts, and the functionality of the brush is superior to anything else I've owned. The flow control is great.
An airbrush is an investment, especially if you're a serious modeler. If the quality of the brushes wasn't superior, then there'd be no reason to produce a $300 airbrush. It's like cars...a $8000 Hyundai will get you where you want to go, but a $40,000 Vette will get you there faster. They both serve the same purpose (getting you from point A to point B), but there's obvious differences in the quality.
All that being said, an Iwata HP-BCS (my everyday brush) costs about the same as a Badger 150 double action...MisterArt.com lists the Badger for $94 and the Iwata for $100, and that includes the hose and color jar.
Yes, there are very expensive airbrushes out there (I have three Iwatas, an HP-BCS, Micron CM-B, and an older CM-C+). 90% of the time, you'll never need more than the basic HP-BCS...
As for compressors, the big noisy Sears brands work, just remember to fill the tank BEFORE everyone in the house goes to sleep!!! I had one for a long time (Campbell Hausfield) but broke down and bought a nice dual head compressor with a foot pedal, it's real quiet and pushes air up to 80psi, almost 4 times what I normally spray at.
Jeff