Best coverage, easy clean up, cheap...
http://www.cartooncolour.com/catalog/index.php?cPath=1
They are used by old school animators to paint the transparent sheets. Need to be smooth, so as not to see any brush strokes and they need to cover 100% so that the background sheets don't show through (with being back lit on top of that...). Of course that doesn't apply to transparents or tints from Cel-Vinyl...but still...
They are more of an artist's selection, which means you will need to do more mixing to get the right shade of green or grey...but for coverage, I haven't seen anything that compared to them. Not the Foundation Paints, not P3, not Reaper
HD...nothing.
If you paint predominately plastics - they have an added benefit of not needing a primer coat.* The vinyl acrylic base is a pretty good adhesive in its own right, and again being designed to be painted directly onto the flexible plastic cel sheets, they stick to PVC, HIPS and even clean resin well enough.
* Not that they don't gain some benefit from a primer coat - but when I am painting things like a clear resin figure for effect or some of the transparent PVC stuff (or canopies...), I will often use Cel Vinyl for my base coat so I don't need to mess with priming.
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Other than that - not much more to be said that hasn't been said. Pretty much any of the acrylic paint lines are reasonably comparable. Questions generally fall to cost and availability more than anything else.
Using what you can get from your local store is a good idea. Running out in the middle of a project and having to wait a week to get paint sucks. However, in todays age of simple online shopping, it isn't a huge factor.
If you don't have a local game store that carries the regular hobby paints - Michaels and Hobby Lobby normally carry Testor's Acryl paints which are just as good as any of the hobby paints. Art paints will work as well - but are a bit of a hassle (even the fluid art paints are thicker and will need to be thinned down quite a bit).
And then of course, you do have craft paints. Available in pretty much every Walmart and other big box store across the country. Bit lower in quality - but serviceable and dirt cheap. Easy to get another bottle at 2
AM on a Saturday night if need be. Consistency tends to be the biggest issue that I have noticed with them. One bottle will be silky smooth, and the next from the same brand and the same color will look a bit like they used gravel for pigment.