[darkgael]

JG: The Burris, if it is like it's cousins, adjusts automatically to light conditions. The Aimpoint has a rheostat that allows for shooter adjustment. There are, IIRC, nine levels available on the Aimpoint. As with all sights of this type, indoor or low light shooting is not where problems surface; it is outdoors, very bright light may overwhelm the dot on some. The Aimpoint has an extra bright setting to avoid this.
About alignment - if you have never used one of these before, there is a learning curve, albeit a short one. It is not uncommon for a first time shooter to "lose the dot". I have seen this happen with both tube style and reflex sights. The Aimpoint may be easier in this respect. At this point, though, having used both types of sights for many years, I'm not sure about that.
I prefer the small reflex sights because they weigh less - ounces less. The Micro weighs 3.7 ounces; the Burris is less than half that when mounted.
Pete