I snapped a green Tru Glo Glo-Dot II onto my Winchester 1200 Defender.
I also have these on both of my old Springfield 67E's, a 12 and a 20, that I use for hunting.
I like them. They are inexpensive, easy to pickup and see in both daylight and lowlight, and they have been durable for me. The length of the fiber optic also seems to make it easy to align instinctively.
They also come in red, if you prefer.