A couple of things to remember,
A longer pistol has better muzzle velocity and sight radius. The bullet leaves the muzzle faster, and it is easier to aim accurate. In real life, these differences may be negligible.
The 19 frame is a touch smaller. If you have big hands, you might like the 17 fit better. I had a .22 conversion kit for my G-22, and that made it a lot more convenient to practice with.
I was raised by a purist. He taught me that (in life and death situations especially,) the mission is always more important. Pick the tool that is best for the job. What you honestly find is, comfort from the frame size is relative anyway. If you aren't used to carrying at all, a very small gun will be very uncomfortable to you because you aren't used to it. If you have a Desert Eagle, you might be so enthralled by the fact you are allowed to carry it, you can put it in a shoulder holster and it never seems uncomfortable to you because you like it so much.
I also have a bit of a problem with the industry telling me I have to have a different gun for everything. I'd like to think I am comfortable with my primary pistol, (I now carry a full-size Kimber Custom II 1911,) and I use it for every day carry, I carry it when I hunt deer, I can convert it to .22, (if I had time and money) I could compete with it, and if I wouldn't get into serious trouble for it, I would carry it to war. If I have the gun that does everything right in the first place, why would I be convinced it is necessary to have a compact version of the same thing for a VERY little bit of comfort?