Ross - there are basically 3 flavors of Vallejo, the Model Air formulated for airbrushing and prethinned, Model Color for brushing or airbrushing after thinning, and Game Color. The first two basically have the same colors just different thicknesses. The Game color is for painting figures and miniatures used in gaming so not much good other than for uniforms and flesh tones.
Using them is easy, I use Krylon primer to get the surface ready (not a necessity but I always like to be over careful) the paint comes in squirt bottles with a little dropper tip so you can really get precise in just how much paint goes in the brush. Squirt it directly in the cup and spray! Or thin as well if using Model Color. I use a LOT less paint because I can squirt it directly into the airbrush a drop at the time and refill on the fly without having to reach for a pipette and such.
The pigments are ground extra fine which is why I think it gives such a nice smooth coat. It also aids when spraying fine small detail with acrylic as there is less tip dry usually associated with acrylics. (but still a little tip dry... it is still an acrylic at heart!)
The Vallejo thinner has a retarder AND an adhesion agent to it so I always use it exclusively. This is where the difference shows through with it and other acrylics when using their branded thinner. The Vallejo thinner is $4.00 per 32ml bottle, but again because you use the built in dropper tip on the thinner as well to measure, there is no waste. I've used the same bottle for over a year now on about 15 or so models and it is still 1/3 full. You can also thin with distilled water, and I do at times when I am spraying very small detail.
If you like acrylics I really recommend trying them. I think it will open up a whole new world of spraying for the average acrylic sprayer... I was able to put mottle on a 1/72 FW-190 with no probs because of the reduced tip dry.
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As far as the sig, thanks... 200+ yr old words that still ring true!