Both the 30 and the 36 are Glocks version of a compact. The 36 is the thinnest and as minuimal as it gets in 45 acp. I used to have and wish I still had a G30. Fat and stout but it shot excellent and never a hicup. If you like the size and Glocks in general I think both are good choices. If I were to do it over again the G30 SF with the slightly slimed down grip would be a strong contender. Length and height they are both about as large as the G19/23 frame. The 30 is much wider and the 36 is just a hair thinner than the G19. To get smaller in the Glock line up you'll have to consider the G26/27/33 in 9/40/357 sig respectively. They do make a 45 GAP in a sub compact but I am not familiar with it or the GAP cartridge. Hope that helps.