I've only used the water-based acrylics in my chinese airbrushes, and never had any problems with leakage through seals. I don't use any harsh cleaners, generally a mild liquid soap, and every now and then, deep clean them in an ultrasonic cleaner. The needles are rather fragile, and bend very easily, and they can be a bit rough - I generally grind mine on a porcelain tile ( I use Jewellers Rouge, but toothpaste can be pretty effective. ), this can really improve the performance. They aren't as slick as an Iwata, H&S, or Badger
airbrush, but of course you are only paying around 1/5 the price. I still use mine for prime coats, and overall basecoats - good for learning the basics
Dave