Trim paint I use whatever is spec'd. One builder likes Pro Classic acrylic, one likes the alkyd/acrylic, and one likes the Porter Advantage 900.
I sometimes handles the service calls for another builder, his guys use BM satin Impervo. I used it when I did a few houses for him, for the money I wasn't impressed.
The builders here all spec one type of paint or another and that's what we have to use. Sometimes if a decorator is involved I get a little more of a voice in the matter. I have one decorator I work for who loves Sherwin's Emerald and will gladly pay the extra cost of me using it.