Don't read Sword of Truth. It is horrendous.
No kidding. So many problems with that series by the end. At least he proved that writing half a book from the perspective of a complete idiot is a terrible idea. Then Chainfire was like reading the same chapter over and over. Hey Mr. Goodkind, if you say it enough time maybe people will have no choice but to agree with your ideas. My brother bought me Phantom so I forced myself to read it, but that was it for me, and Phantom was actually better than Chainfire.
I've got to admit that that was kinda my problem with reading past The Gunslinger. Usually, it's very hard for me to finish a series when everyone I know tells me it tanks mid-way through. That is why I won't even think about picking up the second book of "Wheel of Time".
I'm rereading Wheel of Time right now. The problem in the later books is that they stop becoming books and just happen to be a massive plot with numerous threads. Each book has less focus, which coupled with his meandering style really brings the per book pace down. If you wait for years for a book, that sucks, but reading them straight through it isn't as bad. I think Wheel of Time would have been better suited to simply make about 3-5 parallel books at some point, each focused on a particular thread. However, I don't think the series really changed a whole lot. I actually felt book 1 was pretty weak for the series on rereading it, largely because I felt it was slow paced. My favourite book in the series is #7, and the greatest scene is probably in #9, which is right over where people complain it starts tanking. What is a bad book is #10, although I have a hard time faulting him because it was a cool idea(that failed miserably).
Unlike other series that tank, at least Wheel of Time is paying dividends at the end, all those threads that have taken books to work through are coming together nicely. Over the last few years it has surprised me how much I still care when I've gotten the new books, so I still love it. However, the issues are hard to deny, I don't typically recommend the series to any one. ...at least not without describing the issues most people complain about.