Also, what someone said above about it being boring - yes, it is. Yes, you also go through an intense panic attack the first time you see someone going under, but it does get better.
Being able to compare the role with an Attractions role, I think for the sheer guest interaction part I would choose Attractions over Lifeguarding any time. I would rather be able to talk to people than stare at water for 8 hours + a day.
Also, in summer it is HOT. And I mean HOTHOTHOT. One of our lifeguards fainted on stand, and I almost went down myself at one point. You've really gotta concentrate sometimes, and remember to hydrate yourself regularly. It's very different to being a 'normal' CM.