I am very happy with my Burris Fastfire III, 3 moa dot.
Rated to withstand 1000 g's of force, and will ride on top of a slide no problem. There are a variety of mounts to attach it to most major firearms. Its waterproof enough to be submersible in water. Weighs 9oz, low profile. Hast 4 brightness settings. Auto adjustment, high, medium, low intensity. Exterior is made of steel, and it comes with a nice protective cover.
Can't think of anything bad to say about about it, quality product. Very happy with it.