i think the opposite is true - plastic (really an engineered polymer - EP) is typically better regarded than the brass. there was an issue about a decade ago where brass fittings were stipped of their zinc by the water essentially corroding quickly and had to be replaced. I don't remember the brands that had the issue but I think most of the major ones were involved. I wonder about the newer "lead free" brass too and if there will be some issue in the future with them where the chemistry of the brass has been changed to meet new lead standards. I tried searching for how brass made to combat dezincification was again changed to meet lead free but couldn't find any discussions. Anyway, I've used the EP stuff in as many ways as possible and only used brass where I had to (MNPT and FNPT fittings for instance). I've never heard of any cracking issue with EP.