I would buy the best airbrush of whatever brand you can afford, and as mentioned above, afford to maintain. But do get a brand name brush, you will get better customer support usually, and you will know if you have problems with any techniques, that it is less likely to be a problem with the brush. After a bit of hit and miss, I settled on an iwata hp-cs, as I felt comfortable with it in my hand, and it is an all rounder and suitable for the stuff I do. I would think about what you want to paint with it, if you are wanting to do t-shirts, for example, then an expensive micron, which does super fine detail, probably isn't necessary. Also try and actually hold one if you can, to see if it feels comfortable. Good luck.