I bought it in Holland, and knew absolutely nothing about boats when I started out. My thought was that the only regrets you have when you get old are all the things you didn't do. Besides I'm enough of a businessman that I'd be able to sell it without a loss if it didn't work out. So I gave it try.
Four years later I'm still here and wouldn't want to live any other way. The boat is paid for so my only expenses are $200 a month in harbour rent and roughly another $200 a month on repairs. Internet isn't a problem since 3G is everywhere now - I can surf hacker news while at anchor somewhere off the coast of Sweden.
The upsides are pretty obvious: A gret free lifestyle, beautiful views, ducks right outside your window and the ability to go anywhere you want (within limits...)
The downsides are that it's cold in the winter, you don't have a lot of space, and you need to become a bit of a handyman. I've bought powertools I didn't know existed five years ago.
But overall it can only be recommended. Oh, and drop me a line if you're ever in Copenhagen I'll take you for a trip through the harbour, it's beautiful just before the sun sets.