If you liked the Glock 26, then get the Glock 19. If you didn't like the grip and trigger of the Glock 26, get the M&P. But you'll end up getting the Apex trigger kit for the M&P eventually.
Probably more holster options for the Glock, too...since it has been around for so much longer.
. are these two equal or the G19 has a smaller footprint?