The vast majority of models I have made over the years have mostly been painted with either Humbrol, almost exclusively in the early years, and then Tamiya acrylics. I started to use them more in the 70s and 80s because they had some very useful paints such as metallic finishes and clear colours. As I was into model motorcycles at the time there were very useful.
Consequently I still like enamels for ease of airbrushing, dry brushing and obtaining a good gloss finish and I still use Tamiya acrylics for convenience and various weathering processes. I also have a vast collection of water based acrylics, mainly because I had the chance to buy them for next to nothing. I do use them for figures but not much else so they are a bit of an indulgence.
There are also oil based paints, which are really handy for creating rust streaks!
I used to have big challenges airbrushing acrylics and ended up with a clogged airbrush after a few minutes. I gave up and used only enamels. Then I did a weathering course where the chap told me that water based acrylics in an airbrush were always a challenge but Tamiya paint works very well. The process is this:
1) Buy a new pot of Tamiya acrylic paint.
2) Top the pot up to full with Tamiya acrylic thinners.
3) Add two ball bearings.
4) Shake well.
This paint can now be used directly from the pot in the airbrush. The technique works very well and the paint flows beautifully in the airbrush.