There is a lot to do in CSL, with a huge shopping mall and streets lined with shops, but it's a huge tourist trap. People were coming up to us constantly, asking if we wanted to buy necklaces, bracelets, etc., even when we ate at a small corner restaurant. I'd recommend San Jose Del Cabo shopping over CSL, as it seemed nicer there.
Medano Beach is big draw, with a safe swimming beach and all kinds of water sports.
Nothing is cheap. You may be in Mexico, but they know you have money, so be prepared. Every little thing someone wants a tip for. We heard the nightlife was fun, but if you're not there for that, I don't know that I'd recommend CSL.