I think that the problem with Hasbro's paint jobs its not just cheap paints but also a more marketing driven mentality. While the Japanese try to stick to character colors (generally not always), Hasbro tries to implement brighter more 'eye catchy' colors that would stand out on a peg or shelf so that the product is more appealing to the stores rather than the end consumer - Of course this isn't always the case as in some rare occations Hasbro will pull a totally bland and 'WTF?' color scheme such as Universe Powerglide or Silverbolt.
A recent example that I can think of is the horrible colors of Universe Dinobot.