I have a friend that has one of those Tamiya spraywork sets. I'ts pretty basic and as it has no air tank it pulses air, making painting even lines pretty hard. It is mostly plastic. Also you cannot spray very fine lines with it.
I would reccommend a Badger 150, pretty simple to use, double action and has three head and needle sizes available. I've had one for over 15 years. A compressor with an air tank is a good idea, it's what I use, but as with all air sources it's really the regulator that makes or breaks it. Some people swear by CO2 cylinders.
I guess you're likely to get as many different answers as there are air brushes, since everyone has their favourite!