I really like them.
Easy to install, (you can install/remove with the handguard in place) and you can adjust the tension on the ball detent for that perfect amount of hold, regardless of the wear on the upper.
I've used on both 5.56 and .308 AR's and the fit has been great.
These and their LINK picatinny rail sections w/ built-in QD mount (work on both Keymod and M-Lok handguards) are my two favorite Strike Industries products.