It was okay and just okay. It has some interesting ideas, like the fact that the whole humankind is now living inside a giant MMO. And the possibilities of this MMO are fantastic, like the planets dedicated to fictional universes like Star Trek or Whedonverse. I think that if you allow yourself to daydream about those possibilities you will enjoy the book, or at least enjoy the idea of Oasis.
But setting that aside... I deeply dislike the way it's written. The references to 80s pop culture and geek stuff from every period of time get too overwhelming. Another problem is that if you, like me, aren't related to every reference you will eventually get bored of them or just read through them. Besides the references really don't move the story forward (except of course when the main character is inside a recreation of an 80s game or movie), but mainly the references are just there without explanation or purpose.
Another thing I didn't like its that the real world aspects are too simply solved. For example, and the following will be a spoiler, when Wade gets attacked irl, he solves this by hiding... But am I supposed to believe that a huge multinational that practically controls the world... Would have stopped there?
But possibly the biggest problem is that it's too shallow, its exploration of the topics it touches, like the way technology isolates us and yet brings us together never goes anywhere. The topic is there, it's mentioned, but like the references to pop culture it's not explored.
I think that if the author had been less interested in referencing every single pop culture article he could think of and actually deepening in the characters and storyline, the book could have been way better.