I have a 17 (9mm) and a 21 (.45). I am not sure, but I think the 17 is the most widely used by law enforcement, followed by the 21 as far as popular Glocks with the LEOs. They are great, simple, easy to maintain weapons. Both of mine are the full size versions.
I love the 13 round capacity of the 21, and the staggering 19 round capacity of the double stack with the +2 plate. That is some serious ammo, and give you a lot of options. My 17 stays in my "bug out bag" with an extra loaded clip. In about ten seconds, I can be ready to deliver 38 rounds of fury to any intruder.
Now, there is almost no way any sane person would break into my place, cause my oldest two sons are almost as big as me and pretty solid (for a couple of punks). Still, I rest better knowing what I have. Your revolver for home defense is fine, but it would serve you well to get a 17. With the new spring in it, you can unload those rounds in a hurry with very nice precision. I just use the standard 3 dot sights, and I don't really think about how I am aiming anymore, they are very natural. I am pretty good with that weapon, even though I maybe only shoot 2 or 3 times a year.
Bullets are too damn expensive to shoot like I used to. Me and #1 dropped $250 this weekend.