I have a few friends who shoot glocks. Most of them have the 17 and shoot production in USPSA. That is a great place for a beginner and an intermeiate shooter. I think USPSA is a blast and I really like the game and the situations. I also have a buddy who has the 34, it too is production legal. A real good shooter if you are a Glock fan.
It sounds like you will not need anything more then production if you are going to use the same gun for home protection and to compete. Either one is good. I do not shoot IDPA very much. It is more draw from cover carry situation kind of game. Not aplicicable to you from the sound of it.
Good luck have fun be safe!!!!