Had exactly the same issue and the plumbing was a pain. Saying that, it amazes me how quickly we seem to get through 4 liters of water and seem to be forever filing it up. Iced water is nice on tap though.
Aussie ones are the same. I went for economy rating, non plumbed water, no ice as plumbing was going to be a pain. Capacity, they can look big but not have a great capacity. Also looked at regular items I wanted to store and checked shelves for height like drink bottles and milk etc.