One quality that is important no matter how experienced the user is ease of cleaning.
My go-to airbrush is a nearly 40 year old Badger 200 single action bottom feed unit, but it is a hassle to clean the internal paint channel. I have taught several friends how to use an AB with the Badger, and they all hated the cleaning process.
I also have a double action Iwata with a fixed cup gravity feed, and in contrast it is so easy to clean. The only reason I use the Badger is that I still haven’t mastered using a double action AB. After 40 years.