Well after installing them on my SR40, which is my competition gun I have mixed feelings about the big dots. Observation number one is that they are great at the closer distances. Observation number two is they are wonderfully quick developing your sight picture from the draw, low ready, compressed high ready and transitioning from target to target.
That all said I will be taking them off my full size 40 and be putting them onto my compact, which is my EDC. The main reason for this is at distances of 20 yards plus I have found I can't hold a consistent group with them, and that isn't going to work for me competition wise.
The company literature states the correct sight picture for 15 yards and in is cover the point of aim with the dot and have the whole dot visible and above the notched v rear sight. This sight picture works great! The same literature states for distances greater then 15 yards to align the dot and rear the same but to use the top of the dot as your point of aim. This sight picture does not work great unless you want consistent groups 8-10 inches low of your point of aim. I found after 300 rounds at 25 yards, using the same alignment point of aim and point of impact coincide when then top of notched v/ bottom edge of the big dot is the point of aim. Problem there is when shooting paper you are covering and obscuring the target and having to split focus between the front and rear sights. This goes against everything I've learned/know about proper sight picture where focus should be split between front sight and target.
Since statistically most gunfights occur between 3-10 yards and at night I feel comfortable enough with the performance of the sights to use them on my carry weapon. I will be putting the stock sights back on to my IDPA pistol for now, and will be looking into getting a set of the Novak fiber optic sights as a future upgrade to that gun.
Hope this review helps, experiences may vary, I have seen videos of the big dots banging steel plates out to 100 yards.
[FONT="]I have XS Big Dot night sights on an XDm compact .45 and like ArizonaHeat they are great daytime up close. At night the front dot is much smaller and kinda hard to align front and rear. I ended up with a light on that gun which negates the glow at night and gives me a great sight picture. To me, daytime, 15 yds or less they are great. At night get better night sights. For longer range (over 15yds) try something else.[/FONT]