ORIGINAL: maytom
While I never tried using one, from all I've ever read about them, the "Aimpoint" line is rated #1. While not cheap, you do get what you pay for with these!! I seen first hand one of those BSA Red Dots fall apart from only 3 shots out of my buddies 11-87 turkey gun. If you want quality, it's going to cost you some money!! Same for scopes.
http://www.aimpoint.com/
yeah I have heard great things about aimpoint. If I was in the military or going out west and wanted a red dot I would consider one for sure. I have also heard several stories on the BSA's true glows, and pine ridge units falling apart.
I will say I have shot almost 40 turkey loads 3 and 3.5" through my Benelli with my Mueller and it has been great. $119 cant beat the price for the features plus if it did fail I can still look under it and use my bead sights.