Just curious - what's the difference between the two?
You can book pets for a longer period of time in the Rathskeller Inn (31 days vs. 21) and with a GA, only the resort has an option to check in all your pets at once for the selected time. It costs a little bit extra per day to use that option, but I don't remember how much off hand (I think it's an extra 50 sP per day though)