While looking for something to fill the LONG void between the A Game of Thrones books, a number of people recommended The Wheel of Time series. I decided to jump in with the first box set (The Wheel of Time, Boxed Set I, Books 1-3: The Eye of the World, The Great Hunt, The Dragon Reborn). While quite a bit different than A Game of Thrones (significantly less sex, violence and tamer language), I found the Wheel of Time world to be engrossing, and knew I was in for the long haul. The second set of books didn't disappoint.
Honestly, I enjoyed this set of three books more than the first three. In particular, we get to watch a number of characters grow and change in ways we couldn't anticipate. Rand, Mat, Egwene, and the rest grow and change (I wouldn't necessarily use the word mature), while a number of characters and plots bloom around them. A constant criticism of this series is that the world Jordan builds is simply too big: he never ties off a plot neatly, while instead introduces several others. While I'll admit to losing track of some plot lines in the later books, I think that by reading this series consecutively (i.e. no 1-2 year breaks while waiting for the next book to come out), Jordan's writing shines, and the reader is able to more easily keep track of the wealth of characters and happenings that make his world so very rich.
I highly recommend them to anyone who enjoyed the first three. If you didn't enjoy the first three...I suggest you probably try a different series ;).