If your going to get the Vtac sights, buy the handgun that already has them installed. The sights alone they are selling for 240. From all the reports I hear about the Vtac sights, they have a problem with the fiber optic sights popping out. I would hold off till the Gen 2 sights come out.
I have always put Trijicons on all of my M&P handguns. I just had some Meprolights (Orange rear and green front) they are awesome.