All paints have their pros and cons. With plastics you need to make sure you don't use a paint that will eat/melt the plastic.
It comes down to how much time you want to put into the paint job and what tools you have.
Sending it off to be dip coated is one option.
For the best results you will need an airbrush or spray gun. Use a good primer. For plastics I like vallejo grey primer (
http://www.acrylicosvallejo.com/en_US/primers/family/22). It's a polyurethane so it shrinks as it dries so any texture detail is not lost and it provides a good surface for paint to stick to. You want as thin of a coat of primer as you can get and still cover the surface. The primer needs to dry very well, U usually let larger items sit over night, miniatures I let sit for an hour or two.
For color on something like a keyboard case or computer case I would use Createx Wicked (
http://www.createxcolors.com/products/wickedcolors/) using super thin coats. It should take you 4-6 coats to cover where no grey is showing through. If not your coats are too thick. Let each coat dry for 20-60 min before going to the next coat. This helps the paint stick and not rub off so easy. These are soft acrylic paints so a clear coat is ABSOLUTELY required. After you put on your final coat let it cure overnight.
Once it's fully cured your ready for the clear coat. use a tac cloth and wipe down the surface as you don't want a single particle of dust under the clear. If you are good with an aerosol can USC Spray Max 2k (
http://www.spraymax.com/index.php?id=361&L=1) is very good. It's a two part clear that mixes in the can so each can is a single use as after about 6hrs it's no good any more. It's also important that it's mixed very well so vigorous shaking of the can for 5min (the directions say two) is best. Use a good respirator with this stuff and get about 3 coats on, you only need to wait about 2-3 min between coats or you get some odd layering.
