I have the dual illuminated (DI) on both my pistols.
No batteries, no switches, no electrical issues, but:
I have one amber and one green dot version.
For me, the amber dot is easier to see under certain conditions. Other people have reported that they are better able to see the green dot.
Before you buy, try to look through one of each to see which one works best for you.
For my old eyes, the DI models just weren't bright enough, especially in low light. (in fairness, I generally feel the same about tritium night sights.)
With the LED adjustable models (RM06, RM07) I have control over brightness and can tweak the brightness to suit the conditions... I typically leave the dot on the 3rd brightness setting during the day but bump it up to 4 on brighter days and then 4 or 5 if low light use with a flashlight and/or WML is a possibility.
I did not care at all for the auto adjust models. We just didn't see eye to eye ... and they were pretty slow to respond to changes in lighting conditions IMO.
