My personal favorites are Trijicon HD (XRs) with the orange post.
My least favorite are their blacked out suppressor sights; I wouldn't say that I am any less accurate with them, but the time it takes before I am confident enough to break the shot is SUBSTANTIALLY increased!
My eyes do not work very well with blacked out sights either. I have a black set of suppressor sights on one of mine but only as a backup to an RMR.