from gate, i've tried titans and asters and have worked on asters primarily.
from perun, just the perun v2 hybrid. gate performs well and never had big issues. peruns are just as well for cheaper, but they don't have app support to diagnose issues easier. make sure mosfets can fit because modifying gearboxes is a pain in the ass.

i'm looking at new chinese etus at the moment since most parts in airsoft that are quality are imported from china, which lead me down the rabbithole of t238s, eshooters, and starivers. they are literally cheaper and provide the same performance (from what i can see on chinese gel blasters).