Ive got 4 M&P's. One has Dawson fiber optic front/plain black serrated rear, great for the range where they can pickup light, suck ass for anything else. Thats NOT a knock on Dawson, just a drawback to fiber optic sights, but its a comp gun anyway so doesnt see service anywhere but the range. One has Warren Tactical's on them, overall I like them, but probably wouldnt buy them again(they were one of the first to have the bigger front that is also a different color than the rears) since I think there are better choices out there(like the Trijicon HD's, Ameriglow Pro's, etc...). The other 2(shield and MP45) have Ameriglow with the pro front and 2 dot rear. I like these the best. I think they are a clone of the Trijicon HD's. Customer service has been good, construction is good, no complaints yet(only had them about a year or so).
I have really fallen in love with the front sights that have the big orange or yellow ring around them and a subdued 2 dot rear. For some reason I dont like single dot rears or no dot rears on a carry/defensive gun, just a personal mental block I guess. I think the fronts with the ring around the tritium marry the best of the fiber optic(excellent speed in daylight) and low light with the tritium.