Until recently, I have always used 2 stages triggers, but lately for PRS I decided to try single stage.
The idea being that PRS is fired in a 90 second window and I was hoping the single stage trigger would provide a better reaction time when things were aligned. That was the theory anyway...
Well, after considerable testing and debate, I have learned that I do not care for a single stage trigger (on a rifle) and I'm migrating back to two stage.
Part of the reason is that a two stage can feel lighter than a single stage. Think of it like this... A single stage trigger set to 2 pounds needs two pounds of force, but a two stage trigger set to two pounds can use the first pound in the first stage and the second stage goes off after only one more pound. In this sense, the two stage trigger feels like a one pound trigger.
If you are on the fence, you might consider the new trigger from Cadex which can be set by the user for one or two stages. That way you don't get stuck with a trigger you may not like.