It is a lot easier to conceal a big gun than most people think. The key is a good quality holster. Personally, I think that carrying a heavy gun can be somewhat fatiguing over the course of the day. That is where a lighter gun may be a better choice for many people when it comes to CC. More of a matter of comfort than concealablity. I have been looking at some glocks myself, purely for all day comfort reasons. Of course my daily carry is a S&W 629 with a 6 1/2 barrel, so a glock should be barely noticeable! Yes, 629 conceals very well in a shoulder rig with a light jacket or my 511 tac vest in the summer, but I never forget it is there.
Both guns your are looking at are good choices. I would put my vote in for the 36. Good luck!