I used a Timney drop-in on my first build because 1) it had a good reputation and 2) I wasn't sure of my ability to install the pieces of the trigger group. It worked well and I am still very pleased with it. I took the stock trigger group that I had removed and sent it to Bill Springfield at TriggerWork.net to have him rework it. He returned it within a week--cost $35. I used it in my next build and was amazed to find that I actually liked the the Springfield trigger better than the Timney--4#, clean break, no creep. In addition, I can actually install the re-worked trigger pieces faster than I can install the modular Timney. From now on, only TriggerWork.net for me.