This sprawling onsen hotel, with its escalators and kiosks and constant buzz, feels a bit like a gaily decorated airport terminal. That's not meant to be critical: with 24-hour complimentary use of the excellent bathhouse, Onsen Tengoku, this is a fine place to stay. Go for the Japanese-style rooms (the Western rooms are rather dowdy). Meals are served buffet-style.
Note that wi-fi is only available in the Honkan (main wing) and Minami-kan (south wing).