Ergonomics, more common pointing grip angle, price. Things the glock in its current design will never have over the m&p. everything else is a wash and depends on the shooter IMO. Trigger argument is irrelevant. You can get apex stuff which brings the price up in line with the glock and is much better than any glock trigger when done. Or just do a DIY job for cheaper and it fixes all problems with the mushy gritty trigger syndrome. They're both great at what they do.