I have a stock CMMG in one, a RRA in another with JP springs and a Chip McCormick in a third..The CM is a single stage and the others are two stages...Memory says that I paid about $170 for the CM and about $85 for the RRA with springs...
For the money, the RRA is the better buy, but the CM is less potential trouble since it is less prone to collecting debris, such as dust or powder, should a bullet bounce out of the case...The RRA can be tweaked as to trigger pull weight, while the CM is fixed...
My only experience with Timney is the one that I have in my 10/22 and the one in my Mauser action 6.5 Creedmore and it has be professionally lightened to a matter of ounces...Not something I would suggest for an AR...