I currently own two optics, and my favorite is the Sig-Sauer STS-081. It's a lot like an Aimpoint mirco, but way cheaper. I picked it up for about $100 at a gun show in Georgia, and I hear they normally run for $150 or so. Apparently this is the same sight Sig's AR's were equipped with, so that pretty much sold me. Initially I had no idea Sig even made optics, and since they're handguns and rifles generally have great feedback, I decided to give it a try.
I set it up on my Golani, and it cowitnesses perfectly with my sights. For such a heavy rifle, I really wanted an ACOG or some high power scope to go with it, but I can't imagine using anything different. It's held zero, and was incredibly easy to get zeroed in the first place. The brightness its pretty impressive as I can easily see the dot at level 7/10 outside, with the sun to my back. They also come with a honeycomb, which is pretty dope.
They normally come with a heightened mount, and that same mount has an angled portion so you can still use your irons if you so choose. The battery life is pretty impressive as I accidentally left it on 6/10 for a solid 3 weeks and it was still just as bright as the day I got it. My only real beef is the lack of a QD. It came with two Allen wrenches ( one for the sight and one for the mount, and I lost the mount one), and they're custom sizes. No normal Allen wrench set will have the size that fits either one, so you kinda have to angle a smaller size to grab hold of a corner to take them off. Doesn't bother me too much, but its still a bit of a hassle every now and then.
For something as small, light and well priced as this, you can't beat it (unless you got $$$ to throw around.)