Last month I meant to get a 9mm, but wound up getting a 357 SIG M&P instead. Looks like I still need a 9. I know nothing of Glocks. I can get an M&P 9mm with three mags and tritium sights for 500 dollars. Or I could get something else. So I ask you Glock guys to tell me why I need a Glock. Or do I need to shoot one to understand? Am considering the G19. Tell me why I should get the Glock (two mags, standard sights) over the M&P (three mags, night sights).