1) I've been to both, weekdays during the day are less busy, busier in the evenings. SpaLand hasn't been cruise-y anytime I've been there, as opposed to Jeju which can be.
2+3) As far as I know, the body scrubs are done in the wet areas, and as such, are done by the same gender. Massages seem to be in the co-ed area, but I'll defer to someone who's actually had a massage as opposed to a body scrub.
4) The patrollers are fully clothed with shoes, which is gross when everyone else is naked and has cleaned off in the showers. Staffers at both are not nude.
5) No.
Hope this answers some of your questions.
inevitablesign21 got a reaction from kdrake in Deciding between Jeju and Spaland in Atlanta—questions