I just tried the 4 lb version of the Timney yesterday. I have a 2 stage RRA and the jp single stage but if I upgrade either of the other 2 AR`s, I`ll spend the additional $$ for the Timney.
The friend who just purchased the Timney felt the 3 lb version may have been a better choice, and I kind of agreed, but absolutely no take up (play) at all.