the G2 triggers are usually the most widely-used due to their price. they can usually be had for about 30 bucks or so, and most places that sell AK parts will sell the G2 fire control groups.
the red star arms adjustable is the other one that immediately pops into my head, but it is a bit more costly at around 75 bucks per set. i've been told it's very very very nice, but since none of my AK's are meant to be match-grade rifles, i've stuck with the G2 and been very satisfied.
Now I have another question regarding fire control compliance parts. Single hook/double hook. What does the Yugo M92 use and what does the Yugo M70AB2 use? Does the adjustable trigger from Red Star make a real difference in the pull/travel?
What to thank the first responder for the heads up on red star. Good to know we have a lot of AK friends out there.
as far as i can tell, single/double is purely personal preference. many flats are only machined for a single hook trigger, so if you get a double you'll need to make sure you relieve it for that.
some people say the double hook is a slightly smoother pull. personally i've not noticed any difference. i have both, and will probably be going single-hook on my last few builds just cause that's what the flats are made for initially, and i personally have no "need" for the extra couple minutes of work it takes to relieve for a double. :wink:
Somebody once told me that double hooks will lessen the chance of trigger slap but I would call BS on that one personally. Of course I have yet to even experience that, but that's perfectly fine by me.