I have either factory Glocks or Meprolights and have been happy with both. Both are are and bright, and I almost suspect the factory sights are Mepro's.
I have them on any gun I use, and I keep them all the same, green three dots, to keep things simple.
1) If you train as much as you should your natural point of aim . . . will work pretty darned well.
Yup, it does, and at longer ranges than most would consider, you really dont need any sights. Still, its nice to have the option and sights you can see, in any light.
2) They tend to "wash out" in the muzzle flash when it is dark.
Ive heard others say the night sights are useless after the first shot, but I havent found that to be the case. An easy way to check it out, is just take your gun and your super bright LED flashlight into a dark room with light colored walls. Let your eyes adjust a bit, then with your gun pointed at the wall a couple of inches away from it, and your light at the muzzle pointing at the wall as well, focus on the sights and hit the flash a couple of times. That light is going to be a lot brighter than any flash out of the gun, and youll see the night sights come right back up, with little lag.
The problem I have with night sights is that if its too dark to see your target what real value is a glowing sight? Yeah you can aim. But what are you shooting?
95% or more of the time, its not "pitch black" and you can usually see what your looking at. Night sights also arent just for "night", and work well in darker places or against dark backgrounds during the day as well.
Even if it were "pitch black", and you can literally not see anything, if your prepared, and have a flashlight along, as you should anyway, a quick flash will identify your target, and with a quick sidestep, you can use you sights without the light to shoot if necessary. Works just like a welder drooping his shield and striking a bead.