I started using an airbrush around two years ago or so and made following observations so far:
- a 30$€ amazon airbrush will do for starters. They are surprisingly good. But once you start using it more you want to invest in a better one like a harder & steenbeck evolution for ease of cleaning and wonderfull handling. Just dont buy the better ones, if you only basecoat with it. (Basecoating with airbrush >>> bc with shaker-can)
- the compressor is another thing. You want a compressor with an airtank, so your airflow does not pulsate. And buy a silent one for working late. Who wakes the baby takes it

- Vallejo airbrush colours are great! But you have to use them right. DO NOT try to use the metallics without shaking them properly and without discarding the first drop. Shaking properly: 2-4 minutes without steel balls or 1 minute with two (STAINLESS!!!!) steelballs. And even then, you want to dilute your colours sometimes, based on your pressure and tip-size.
- the optimal liquidity is something like milk. You should mix it with water/thinner as long, as it does not rinse of the wall of the mixing container. When it starts to rinse of the wall without sticking to it, you are fine.
- i use a 0.5mm tip for the Vallejo polyurethane basecoats and a 0.3mm tip for the rest. For ease of use i just leave my old china-airbrusch from amazon with the 0.5 tip and use my more elaborate equipment for finer details.
- Airbrusch-applied-colour is much thinner and more evenly distributed than brushed colour. It is very well suited for light colours, that do not cover well like white and yellow. It is not very well suited for fine details. Brush has no alternative here.
- If you buy an airbrush, do not forget to buy a cleaning pot and other cleaning equipment as well as a suitable filter-mask.
- You can use most of your normal paints with an airbrush without problem. No need to buy special ones. Just dilute the properly. Be aware that some colours are not to be used this way, because they contain dangerous substances like some yellow ones containing Cadmium.