I took it for about a year, and it helped a little bit but not enough to make a huge difference in my life, and I was taking so many pills/day. It just wasn't worth the hassle. Then I tried SAM-e, and it was a little bit better, but still didn't make enough of a difference to justify the cost.
One thing to keep in mind when it comes to alternative treatments: not all brands are the same. When I was taking St. John's Wort, I picked up some brand while I was at the grocery store thinking it wouldn't make a difference what brand I was taking. But after a few days, I started to feel worse and did a bit of digging online. From what I read, these treatments aren't regulated very much, so the level of effectiveness can vary between brands. GNC's St. John's Wort seemed to be the best one for me.
Good luck!