I've got a Timney Calvin Elite 2 stage trigger on my Remington. I was a bit disappointed with it, as I can only set the first stage to max 2lb. The second stage in around 3lb. I would much rather this be 3lb and 5lb respectively, just like my buddies AI which felt great.
I will say though, that the trigger is reliable and crisp. You can feel the build up of the first stage and the second stage breaks with a slight additional amount of force. The first stage is not like "removing the slack" of trigger travel. For example, my Yugo M48 has trigger slack which is taken up as you reach the firing point, but if you release the trigger, then the slack will not reset until you cycle the bolt again. In the Timney trigger, the first stage reset should you not follow through and fire. Having shot a two stage trigger, I feel strange going back to a single stage trigger. I get that precision shooters prefer single stage triggers, but thought this might be some interesting information for you.