The standard that i judge all other dot sights against - Holosun HE510C Elite 1x 2MOA Reflex Green Dot Sight

Love this thing, it has a nice wide view through the lens, the dot and ring are clear and crisp (even with my mild astigmatism), the controls are simple and easy to remember, battery is easy to change (but you won't be doing that much), and the QD mount stays put after having to only readjust it the first day shooting.
The only downside is that it kicks quite a bit of light from the dot out the front glass, so don't expect to be stealthy.