I'm going to violate the principle of your post.
I use the Trijicon Reflex II and it's phenominal. Shots out to 400 yards are spot on--past that with a little hold over. It uses no batteries, and is usable as a night sight (fiber optic with tritium back up)
Yes, it's $300. When you mount it you'll know why. It's ROCK solid, rugged as hell, with positive adjustments that STAY ZEROED.
Now, it does have a problem with wash. If you're shooting from indoors to a target in bright sunlight the triangle washes out and you have to work to see it. I use HK back up iron sights.
Other than that--holy snappin bumholes, Batman, that thing is the schizzle. I have 4 mounted on 4 guns, including a Benelli M1 Tactical and an 1100 Special field for slug deer hunting.
The sight is small, light, and TOUGH. Save your pennies, it'll do ya for a life time.