It worked GREAT for me. Even though it's in the same family as Cipro (which I'm allergic to) I was actually able to tolerate this one. It was great for knocking out my infection and helping get my PFTs back up.
I do notice that I have weird dreams and hallucinations when I'm on it. We've come to expect this now, and a therapist helped me come up with ways to deal with the hallucinations. They weren't that bad, and overall when it came to weighing that against the benefit of the Levaquin, I decided to just put up with the hallucinations and take the Levaquin.
There are some rather serious side effects that can happen, but those are very rare. Your doctor will tell you about them when he prescribes the Levo.