Water Heater...6 gallon or 10 gallon?

Thanks all for the opinions. I tried to respond a couple days ago but got denied by the stupid captcha thing. Anyways, I'm leaning towards 10 gal We almost always camp with hookups, especially when going more than a weekend. And I'm not against using the campground facilities when necessary. I've got 2 daughters (11 and 13yo) and my wife, so we use a lot of water. I just wanted to make sure I wasn't missing some downside that may cause me to want a 6 gal.

Thanks again everyone!
Bob