My long time experience has caused me to be in agreement with the two men quoted in the article Mister X posted a link to in his post. I have tried just about all available sights. I started out preferring plain black sharp sights front and rear. I still prefer them. I have all kinds and use them, but find the thoughts presented by these two men to be a correct assessment of the situation, especially for personal protection needs and use.
As I have gotten older and my vision acuity has diminished, I find that a wider opening in the rear sight is helpful for me and I have modified some of my rear sights accordingly. If I feel I need something extra on completely black sights, I will paint the front sight white or green for a better reference point. I can also easily remove that if I wish to do so. I do not like any sights or dots on my rear sight. I have blackened the dots on my rear sights and left the white dot in place on the front sight on my guns with three dot sights.
The fiber optic sights (green for me) show up really well for me in daylight on the front sight if the front sight is shaped properly around and above the plastic tube. These sights tend to be a bit more fragile than others. Most of my night sights have been in place long enough to begin to lose their strength. The best thing about night sights is they generally let me find my gun in the dark to pick it up!!!
My practicing these days involves shooting at a small paper plate of about 8 or 9 inch diameter. If I can keep my rounds in the flat bottom of that target at any personal protection distance, I'm good to go. I still practice a bit of shooting at 25 yards and out, using the same target and paying more close attention to my sights, but none of the three focals in my glasses allow me to have a really crisp sight picture. I can still keep my rounds on the plate, however. If your gun fits your hand well, if you hold it correctly in relationship to your body (one handed or two), and if you pratice and maintain good trigger discipline, you can do good personal protection work regardless of your sights!
I also carry and use a small flashlight that uses two AA batteries and produces about 100 lumens of light for target identification in the dark as well as for a multitude of other uses. Gotta know for sure who your target is and where it is in the dark!! These things are what work for me. You gotta figure out what works best for you!!!