I have a RDS on what was my mom's Buckmark... and that's only because she lost the rear sight. As soon as I can find one... it's coming off. FWIW, I still kick it old skool on my rifles, too... I have exactly one rifle with a RDS on it, and that's likely to stay that way.
Friend of mine wanted me to test drive his new pistol this weekend... a S&W MP of some sort. Like someone else mentioned, if I have to hunker down and look through the irons to see the red dot, then why have the added weight and bulk of it? Rifles are another story, since you should have a constant index point to shoot from... and that goes for irons, RDS, or an optic. I suppose if I trained on a pistol that fit my hand well, with a RDS, I might become more proficient with it... but I am perfectly happy where I'm at now.