I've taken it in the past and am currently taking it. I've had no side effects but I worry about how it may be changing my brain. I also think it may blunt all my emotions.
It can be a mean ***** if you stop taking it or miss a dose. If you are even a few hours late you will feel the effects.
The effects are pretty much what Squaw described along with a tendency to feel anger bordering on rage.
It does work well for depression and anxiety though.