Airbrushing tends to have a bit of a bell curve in learning, at least from what I've experienced, you tend to make a lot of basic mistakes early on (basically how to thin the paints, use it for basic stuff and maintain it), then reach a point where you can quite quickly and easily do various bits (including some very good effects), then gets harder again as you learn the advanced stuff.
If you get muck on the needle or nozzle you can, if you're careful use a cotton bud with some cleaner on it and run it around the nozzle and needle to clean them in situ, and if you tip the brush back (being careful not to spill any paint in the cup), you can work the needle back and forward with no airflow and that can help
(by leaning it back you stop the paint from flowing to the needle point due to gravity whilst working the needle can move minor blockages forward for the cotton bud)
However if you've had paint drying on the needle or clumping you will need to thoroughly clean the inside of the nozzle out at the end of the session as you are likely to find you've got small bits of dried paint that's been pulled back into it (in the same way you get flakes of metallic paint that builds up quite quickly).
Never leave a brush without at least a thorough rinsing after use, one of my friends sometimes pops round to use our setup and often i'm too tired to clean it fully when he goes, with the result that the next time I go to use it I can spend 45 minutes doing a full, thorough clean up to get rid of the dried paint (even if I leave the brush with a cleaning mix in the cup).
I love the airbrush for basecoating, and fast model work
2-3 minutes to basecoat things like nids is wonderful, especially when you've got hundreds of them.
I think when I did my tau flyers it took about 15 minutes a coat, and took longer to apply the masking than the actual primary colours.
