Recently I discovered Gaianote's paint and had a go with it. This is a lacquer based paint and I found that their metallic series are better than Mr. Hobby's. Its much finer and easier to airbrush. No clogging issues even with the 0.25 mm nozzle airbrush.
I also use Tamiya enamel series paints. I only use black (for panel lining) and their metallic range. Enamels are great paint to work with. It is oil based and therefore very smooth. Enamels dries very slowly and takes even longer time to cure. As such, it self-levels and produce a very smooth surface when dried. I use Tamiya's X-20 thinner to thin them.Their metallic flecks are very fine and won't clog airbrushes, even with a 0.25 mm nozzle.
For hand brushing, I use mainly Citadel Colors with their brushes. Citadel's paints are acrylic based, therefore it is water soluble and you don't need thinner to thin them. Occasionally I use them for airbrushing, mixed with water. Some users say they mix it with isopropyl alcohol for airbrushing, for me I find that Citadel doesn't mix very well with isopropyl. It becomes lumpy and doesn't dissolve well. Citadel makes a very nice range of normal colors, washes and foundation paints. I have some Mr. Hobby Color acrylic based paints for hand brushing as well.
Now I always use a respirator when airbrushing. My current workhorse is the 3M 6200 respirator with the 6006 cartridge. Its dual cartridge and can be used over a long painting session without problem of dizziness. Since it is dual cartridge, you can breathe better without much air restraint. The only con for this gear is that its kinda heavy compared to a smaller respirator. This gear is good, it protects your lungs and makes you look like Darth Vader as well.
This is my first respirator, the 3M 3200 series with 3011 cartridge. It is a single cartridge respirator, it is lighter and less cumbersome. Now I use it for short session work. Extended use is tiring because of the limited air supply through the single cartridge .