Welcome to AR15.com chgreen, I was jes' funnin' witcha. [;)]
But seriously, [u]generally speaking[/u], aftermarket two stage triggers are good for highpower matches, varmint shooting and precision type shooting..., and single stage triggers are good for tactical type shooting, three gun matches, LE rifles, etc. Think of an aftermarket single stage trigger as an "improved" military trigger.
In keeping with the above, I have a RRA two stage in my highpower rifle, and a JP single stage in my M4gery. The Jewell is pretty hard to beat for highpower and it's easily adjusted. The RRA is [u]not[/u] adjustable but it can be tuned up with judicious use of a stone on the sear contact surfaces. The RRA is also about half the cost of a Jewell.
There is one line of thought that triggers on "serious" rifles should not have adjustment screws, because Murphy's Law of Combat says they could come loose at the wrong time. Armed with this information and knowing what kind of shooting you plan on doing with your rifle should hopefully help you decide what kind of trigger you want to install in it.