Thermostatics are used world wide; PB is not. Go figure.
With only one shower head, you only need a 1/2" diameter not a 3/4" diameter thermostatic. Saves you money.
At http://starcraftcustombuilders.com/articleslist.htm are articles that will help you get an idea which company makes products of high or low quality.
P-Pf is medium low. Moen too.
Delta is OK.
Anything above Delta is good, and can get expensive.
Nobody is giving it away. It's not a commodity and they won't make it into one.
Hope this helps.
It's a start.