I run both the Schmidt 2 stage and two PSA EPTs.
For the money both have been great triggers without getting into Geissele or Hiperfire money, which I also have a few of.
ARs are one of the few platforms that have nice trigger options for cheap, IMHO not worth the time to polish a cheap FCG unless you just want the practice. My EPTs are from way back when they first came out and shine like a mirror, I couldn't hand polish that nice.
Some of my builds run surplus 7.62x39 or 7n6 and for those I like to run heavier hammer springs which ruin a good single stage but barely make a difference in a 2 stage.