chrome paint is very rare, and paint can only be used once which makes the chrome paint even MORE rare than it would have been. personally, im gonna use the chrome paint on some rims. i think chrome cars are butt ugly
The special paints aren't really rare if you know how to get the game to give you what you want. There's a thread on this subject in this very forum (probably on page 2 or 3 now).
I honestly can't tell the difference in paints, well except chrome obviously. I'm taking full advantage of this tho, I'm trading my matte and color changing paints for some 24h loans on cars I need. I really only care about blue paints because my cars I use collection is all blue of the ones I can paint.
I even went as far as to trade a maxed at Furai for a stock blue one which cost me 300k or so after maxing out the first and maxing out the new one lol