I would recommend to someone the first three, but then they should stop.
This is strangly exactly what I tell people. Read the first three and pretend it ends there, otherwise you are just wasting your time. Now there are some people who still love the series, but these are usually the same type of fans who make me hate the books even more. You can't even do a WoT RPG with them, because if the even slightest deviation from the novels is found, you will never hear the end of it.
These same fans who actually
do roleplay get even worse. 9/10 times they will play an Aes Sedai and mock anyone who plays a nonchanneler that believes they have even a slight chance of doing anything significant. No one is allowed to play a book character unless they are only going to do a scene out of the book word for word, in fear of changing the story. Which of course leads to the group never being able to do anything of real importance, because anything remotely useful would somehow change the story. So keep in mind that one reason I do not like these books as much is from roleplaying with people like this.
The first two books were good. The begining and end of Dragon Reborn was good, but everything in between was boring save for the occational scene (like when they fight the darkhounds), because RJ took out the main character. Four got better, with a lot of the story about Rand, but ever since that book the story has steered further and further away from the main character and to all the secondary characters. Its now got to the point where you are reading 20 pages about a character who was mentioned once or twice in a previous book and you only get passing mention of the main character.
Its also slowly becoming aparrent that many of the things RJ said about the series is untrue. When people first started noticing the change in tempo, he credited it to moving away from the LotR base he set the first book on. Now it is easy to see the change in tempo was him moving away from the idea of having a central character and going to a bunch of secondary characters with occationally interwoven plotlines (similar to a soap opera). Strangely enough, his fanbase has shifted from young males to older females. This is probably the same reason so many fans complain about the WoT RPG, since it was based off the fantasy world of the first few books instead of the drama of the latter.
Probably the worst thing is how hard the story is getting to follow. The first books, it was about all of these unmentioned things you could figure out by rereading them and paying attention. All of these have been completely revealed at this point, and left in their place are overdone descriptions and even more characters. I've heard a few confused people think its because the answer is in these little untold stories that the first few books had (like how all the main characters had some type of bloodline connection to each other). But nothing is there, the reason its confusing at all is the sheer overwhelming force of all the characters. The books are practically split into 20-page chapters each about a completely different character and plot. The books are also litterally backtracking. Between the end of book 9 and end of book 10, only several days pass. This is because most of the book is a flashback to things that happened in book 9 and even far back as book 8 or earlier. The book will say one thing has happened (that something being a plot advancement), then in the next book you only discover it never happened. Which goes back to RJ's contrived method of "rumors" he set up, where only 10% of what you hear is true. At least he gives readers a clue that most of what they're reading is BS.
I can't talk about this anymore today. The more I think about them the more I hate them. I'm ashamed to even say I've read them (and a lot more than once... its basically a requirement to understand what the heck is going on).