I'll say, investing in a airbrush has been great.
Even if just for base coating and varnish.
The main reason is you can do it inside without stinking the whole place, which means not dealing with all the shitty weather conditions involved in spraying minis outside.
Too humid, too cold, too hot, bugs, whatever.
Nope, just sit down, spray, clean, done.
The propellant in rattlecan also melts a few types of foam (XPS?) and I use it sometimes for terrain.
Airbrush don't melt anything.
With the price of citadel cans you can proudly buy a airbrush for the price of 2-3 cans that'll last you forever.