Nice review. I have a CORE9mm with the FF3 and am thinking about replacing it with the Vortex Viper in order to cowitness with the irons. The FF3 is just a little bit too thick that you can't use the rear sight. How is battery life and auto-off feature on the viper?
OP - something else to muddy the waters for you in this price bracket: The newer Sig Romeo 1. ROMEO1? | Sig Sauer
Do you know what plate adapter works for the Romeo 1 on the M&P? I was never able to find out. It has a few advantages over the Viper IMO.
Well I can tell you one thing I don't like about it already. I don't mind having to take the the sight off to change the battery, I am used to that from the RMR. What I don't care for is that you have to take the sight off to adjust it. Maybe you don't have to, but I am not sure how to reach the lock screws which are hidden behind your rear sight without taking the unit off. Also on my particular example I can't get enough adjustment out of the windage screw to center my dot. That is more than a little bit irritating, but I guess you get what you pay for, maybe some day I will learn that.
After feeling the dials they did seem firm enough that they might stay in place without the lock. I had read they were very lose but I did not find that to be the case. I am not completely sure the fault of the wayward dot is the sight. When I went to pick the gun and sight up today after having it set aside at lunch yesterday, one of the employees at the LGS had already installed it and said he had rough zeroed it. While doing some dry fire tonight I noticed the dot was a bit to the right so I went to adjust it. The lock screws were very tight and when I loosened them, the dot jumped off the screen to the right. Nothing is ever easy.I unlocked my adjustments and mounted the sight. Then zeroed the optic. That was about 10k rounds ago, and the zero has never moved.
After feeling the dials they did seem firm enough that they might stay in place without the lock. I had read they were very lose but I did not find that to be the case. I am not completely sure the fault of the wayward dot is the sight. When I went to pick the gun and sight up today after having it set aside at lunch yesterday, one of the employees at the LGS had already installed it and said he had rough zeroed it. While doing some dry fire tonight I noticed the dot was a bit to the right so I went to adjust it. The lock screws were very tight and when I loosened them, the dot jumped off the screen to the right. Nothing is ever easy.