I spent a couple of hours exploring Second Life over Chinese New Year, and it’s a lot like… real life. Most of what you see reflects how people behave and think in real life — most people make their avatars look human, assume avatar gender reflects real world gender etc. Many norms get carried over e.g. some don’t like changing their avatars’ appearances in front of other people.
You won’t have to go far to find sex and gambling in Second Life, but there are interesting places to see and explore. Svarga comes to mind, but humbler projects include the Peranakan House someone’s built in Second Life.
After the hype and the novelty however, whether you’ll continue to log in or not will probably depend on whether you manage to find like-minded folks and how much you enjoy building virtual stuff. That said, basic accounts are free so no harm giving it a try.