They work for some people, and they dont for others. Like me....i wouldnt touch acrylics with a ten foot pole after what they did to my baby.
Im having to salvage this poor guy from the bin thanks to acrylics:

I will give credit where its due though, because before i transformed him into alt mode the paint looked awesome:

But then i tried to transform him into alt mode and they started chipping off all over the place.
So i decided to shot-blast the red acrylic crap off and just start again and re-paint it black like it was originally and keep him for myself because i was planning to sell the red version but then it got all effed up and thanks to the course nature of shot-blasting im not happy with selling off a figure with the sort of paint job he is going to end up with.
Its not due to my lack of skill, as i have plenty of that but its my own personal standards. The shot-blasting has left many rough areas that i have sort of fixed with sanding and smoothing down but if i painted it red again they would stick out because of the color and i wouldnt be happy with trying to sell something of that quality.
Im a perfectionist ya see.

So now you know why i loathe acrylics. Nope its car paint and spray can paint for me from now on. I'll only use acrylics and enamels for small detailing and highlighting or dry brushing.