DH and I have done this tour 3 or 4 times - granted, we're pop-culture junkies, so we may enjoy it more than the average tourist, but we've never been disappointed. We were there once when they were filming scenes from The Last Samurai, and other times we've seen several celebrities - I'm remembering Martin Sheen, George Stephanopolis, Goran Visnic (who plays Luka on ER), and Lauren Graham (from Gilmore Girls) off the top of my head, but I think there were a few more. Also, they take you to actual working film and tv sets, so it's much more authentic than the Universal or NBC tours. We've always felt like the NBC tour is very condescending and staged, and the Universal tour is, of course, more for the thrill rides. Oh, and a bonus: you're on a tram for part of the tour, so it isn't constant walking!
I think Paramount is offering tours again too (they stopped for a couple of years after 9/11), and theirs is alright, but in our experience, the WB tour is more professionally done, and the guides are much more informative. Plus, the Paramount tour is about 2 hours of walking.
I think the WB tour is about $39, and the Paramount tour is $35.
BTW, we've been in late Jan/early Feb and found it to be a great time for the tour, because nothing is on hiatus during that time.
Hope that helps! Good luck with your decision!