I really liked the DNZ mount; it's lightweight, sleek, and let me mount a 40mm Vortex Viper really low. However, I did have a problem with the ring screws shearing. Happened to me twice, same ring. Now, I'm not sure when the first one happened, but the second occurred on the 16th trigger pull of a range trip (I have T3 Lite in .308). Just popped the hex head right off the thing and I had to drill it out . . . twice.
Take the anecdote for what it's worth; I can't be sure that it was the mount flexing under recoil, or if I did something wrong, or it was just pure bad luck. I had everything torqued proper and mounted according to manufacturers instructions. I ordered a set of Sako Optilocs with the bases--on clearance, direct from Beretta--for 55 bucks . . . they are a little heavier, but are good, solid steel, with four screws per ring, and they too mount right on the integral rail. After 300 rounds they're as solid as can be.