I only got into building AR-platform rifles and pistols within the last year or so. Admittedly, most of my builds have been budget builds, including lowers, LPKs and upper kits from Palmetto State Armory and Combat Armory.
Lowers have largely been built with the standard Mil-Spec LPKs from PSA. Not a big fan of the scratchy triggers, though.
Recently, I picked up a couple of Larue Tactical MBT-2S 2-stage triggers for $87 each recently. MBT stands for 'meticulously built trigger'. They are offered with a curved or straight bow made out of S7 tool steel and come with two trigger springs and standard trigger pins. First stage breaks at 2.5#, while the second breaks at 2# (4.5# total). Use the heavier trigger spring to increase break to 6#.
While it's not a drop-in trigger, the trigger assembly (trigger, disconnector, spring) is all pre-assembled, making installation fairly easy.
Operation is smooth and very crisp, with a solid reset. I've had a RRA National Match 2-stage trigger in one of my other rifles for quite a while, and the Larue MBT-2S seems to be a step above.
Quite a few reviews I've read or watch put in on or above par with the Geissele SSA-E, which is a $240 non-drop in trigger.
For $87 each, I'm planning on picking up a half dozen more and replacing the triggers in all my ARs. You can damn near get three of the MBT-2S triggers for the price of a single SSA-E.