I'm using TruGlo TFO night sights, yellow rear & green front. First time I've used TFO's, most of my other guns have Trjicicon, Meprolight, or AMeriglo sights but I really like the TFO's so far.
I used Ameriglo, three dot, orange front, model SW-251 AmeriGlo Weapon Sights | Complete Sets
It states sold out but it was that way when I called but they had them in stock and hadn't updated their site.
Changed front sight to fiber optic "green", from Dawson Precision. It was made the same height as S&W factory and made a huge difference in target acquisition, in full light and low light conditions. You get both red or green replacement fibers to your liking. I left the S&W rear sights the same ones so no need to adjust site alignment. A very economical and functional upgrade to the Shield sights.