A lot of good info here, but you first need to experience what a 2-stage trigger feels like. The main reason for having one is for precision supported shooting as in a match. I would also think snipers woud appreciate a good 2 stager. Jewel and Milazzo-Krieger 2 stagers are currently the best you can get. Since they are intended to be used as match triggers, their advantages may not be obvious if you just need to fire quickly at close range. Some responses have said that 2-stage triggers are unreliable or go out of adjustment. Well, some of the less expensive ones might go out of adjustment. But, inherently the 2 stage triggers are a safer trigger. I mean that in the NRA sense of the word - they use MORE sear engagement than single stagers, not less! Therefore, if you want to isolate just one of the qualities of this trigger you would have to say it is a SAFER trigger because of the greater positive sear engagement. Wear is much less likely than a single stage trigger that has been gunsmithed for a crisp (creep free) release. Adjustments in an adjustable 2-stage may change, but it is not because of wear, but because someone did not know how to adjust it in the first place and/or forgot the lock-tite. Finally, all this is b.s. until you go out and use one at the range at 300 yards or more.
-WhiteFox