Well, I ripped through it pretty quick and I'll just repost what I put on Amazon here:
Stephen King has graced us kindle owners with a bit of surprise. Coming out a few weeks early, UR downloaded to my Kindle this morning and 90 minutes later I had devoured its 1737 locations.
UR settles into a space somewhere between a short story and a novella. The premise is simple but fascinating. After a mild mannered college professor orders a Kindle, he is met with a pink Kindle that downloads books not only from Amazon.com, but from Urs. Each of the more than 10 million Urs seem to represent a different reality where authors have written different books. Ever wanted to read the unpublished Hemingway book, or six Poe novels? King explores the possibilities and in the process makes every literary mind jealous.
Of course, being King, things start to go wrong and become disturbing when the professor finds out that the pink Kindle can also download newspapers from different Urs. I'll let you discover the rest on your own.
Ur moves quick and features some cameo appearances by past King characters that will leave the most cynical CR smiling. It falls short of five stars simply because it is measured against other great King novellas and novels, but UR is a great diversion for any King fan.