Another factor I didn't see mentioned here, is the Glock 30 is about the same size overall as the Glock 19. I have all 3. (19, 26, 30), and I now carry the 30. No reason not to because of size, and or "concealability".
Also the 26 can use a larger magazine .. So essentially it is more versatile .. Really all your getting with the 19 is the extra .58 or so barrel and a rail.
IMO, best of both worlds if you just have the one gun is the G26 with the regular 10 rnd mag for deeper concealment PLUS another G19 mag (or even G17) with the grip sleeve for when your dress can support the longer handle.I just carry a 26 with a 19 mag in it, with adapter. Which basically makes it a short barrel G19. Works great for me though. Lots o' bullets in a small package.