I haven't had good luck with them.
You have to thin them with their airbrush thinner, since reducing them also reduces the binder, you can't really use water. Also, the cheap craft paints seem to have a lower pigment ratio in them, I wasn't able to thin them to far before they became transparent.
That said, I've had excellent results with the higher end acrylics as Michaels--Liquitex, Winsor & Newton, and Golden. You still have to thin them with their airbrush thinners, but they have a much higher pigment ratio, and can take it easily.
HTH,
Dan