Ey up PP,
I also prefer brushing, though I do have an airbrush which I've "had a go at", just because it's another modelling skill to learn. I like Vallejo too and had a good selection of the model colour range. I just can't get on with them for spraying as whatever I try to use as thinners - water, de-ionised water, IPA or even their own brand thinners seems to make the paint stringy or even lumpy!
What I've also taken to doing is applying several coats of thinned down Model Air too. It works a treat and after leaving it sufficient time to cure, a very gentle burnishing with a bit of teased apart Scotchbrite and then a polishing cloth levels it a treat. After the matt varnish has been applied, it's also great for taking those faint brush marks away and removing the "dead flat" finish to give it a mild sheen, just like the real thing.