First off for information to be useful you gotta know the source. I'm a very low level B class shooter in USPSA Production, shot "Sharpshooter" in IDPA classification the one time I did it, I work for State Probation and Parole thus have had the initial and yearly training for 17 years there, and one had higher level class with Advanced Performance Shooting. Basically being around a lot of shooters from that leaves my self evaluation at: In small local competitions I can do very respectably, I can impress instructors and strut like a big dog in qualification with people who mainly only shoot twice a year to qualify, and I better get my butt on the porch quickly when the big dogs from competition, or the tactical world are about, because they make me look like an amateur. Another factor sure to play in is that I'm 45 now, meaning I'm about 4 years into "needs reading glasses", this may well have played a big part in how much time, money and effort I spent playing with different systems, and height widths of notch and post sights. Now for competition shooting with all taupe colored targets and white painted steel, I'm totally settled that black rear with either a black front (younger eyed guys?) or black with small fiber optic in a thin bladed package is just the bees knees for me. I figure 90% of top competition shooters use this combo for a reason (unless shooting Open Class with a red dot). Below was more in search of defensive pistol sights. Right now I've got two RMR glocks from OST, I've had about 1,400 rounds through combined, a couple of Glocks with Big Dots I've had twice as many rounds through, and lots and lots of experience with notch and post such as Henie, Warren, Trijicon etc.. over the last 30 years . Playing with combinations of sights, using my timers over the last few years, this is what I found from my various timed drills, striving for most speed and solid upper chest placement. 0-5 yards: Nothing mattered, nothing. Big dot, red dot, notch and post Defoors/Warren etc.., bare slide, or having a live goose mounted as my front sight, whatever, just didn't matter. At that close range I'm using draw stroke, body index, whole gun, more than sights. Run after run, never saw any trend of one system being faster than another. 7-15 yards Big Dots fastest, and still plenty precise on full targets, good notch and post sights like Defoors or Warren with thinner blade right behind it speed wise and maybe just hair more precise if that, and then the red dot surprisingly typically a hair slower than good notch and post irons for me, but s detailed below, the longer the ranges or the more precise the shots required, the red dot is starting to creep up on the other two speed wise, and starting to surpass precision wise as compared to say 7-12 yard drills on larger open targets.. +20 yards OR trying for really precision shots on closer targets (eyeball, credit card area of head shot, heavily obstructed targets etc..). Red Dot on slide RULED, period, fastest times and most accurate. Good notch and post sights next fastest and most precise, then Big dots coming in the slowest of all three. I could still make good hits with the big dots, but what the clock taught me was that for me at least, there was weirdly a cross over point at a certain range (for me about 15-20 yards), or a certain precision level at closer range, that the big dots became actually became SLOWER than the other two systems. I'm sure the better you are and the more you use them, the longer the range that crossover point is, but I'm a believer it exist. I think this might be a significant reason the Big Dots are not popular in IPSC/USPSA, not the more commonly held "not accurate enough for competition", but just too slow to use for popping smaller plates or hitting the A zone 20 of 20 times at 20 yards+ away. YMMV Just thought I'd share my journey of trying a lot of combinations over the years and what I at least seemed to figure out for me.