I hate to answer such a serious question this way, but rest assured, I'm being serious. The walkthru I used was on gamefaqs, and I'd imagine the ones on there are going to be more detailed and have more information in them than any of the published strategy guides. I could be wrong, as I've not read any of the published guides, but considering how many pages the gamefaqs ones are, and that they contain stuff like how to glitch the game and things of that nature, I'd think they'd be more in-depth.

I personally find most strat guides to be nice collectibles but not that great for actually telling you everything there is to know about a game. (Except for a few exceptions, like the Star Ocean 2 guide, the unofficial FF7 guide by Casey Lowe (?), as well as the Resident Evil 3 guide in the same series.)