There's advantages and disadvantages to both.
Being self taught I'd say I'm glad I never took lessons.
In the end I learned what I wanted to and wasn't forced to learn theory that I wasn't interested in back then. I developed my ear a lot better by being forced to listen to songs and figure them out myself.
The only disadvantage for me was that it took a lot longer to learn because I had nowhere to get information from.When I started there wasn't any internet so you either had to learn from friends or sneak a look at a book in the music store.
These days you've got video lessons on the web and tabs everywhere so you've got all kinds of places to get info.
I'd say, if you're a good self starter with a mind of your own and enough confidence, and you just want to play songs or join a band, then teach yourself. Maybe take a few lessons to see how you like them or to get some basic questions answered.
If you need somebody to show you how to do things, need somebody constantly pushing you to learn, or if you want to play professionally as a studio musician..take lessons... at least long enough so that you can start figuring stuff out by yourself.