Villa A was large and comfortable with a great little private hot spring in the back. Private hot spring was not filled with water until we requested it, which meant that it was fresh and clean when we were ready to use it. The room also had a mahjong table, which was a fun surprise.
The hot springs area itself was very nice, with many small springs all over so you can definitely get one to yourselves. Nice variety of temperatures, herbs, etc. Some of them were closed for the season, so there was only one cold pool and it required a swim cap to use.
Most of the amenities were near the non-villa hotel area, which is a bit of a distance from the villas. Honestly, there seems to be very little reason to pay extra for a villa. The normal hotel rooms are probably sufficient for whatever you are doing.