I'm quite fond of Rhalgrs. It was a bit more spacious, but allowed you to chill in the water, or on your mount.

Radz-at-Han is a close second. Vibrant colors, and the BGM slaps hard.

I wanted to like S9 (i enjoy the aesthetic personally), but the BGM kills any desire I could have had to idle there for longer. Now if I mute the BGM and put on the CP2077 soundtrack, i become happy as a clam.