Given reviews from Amazon, classify those review based on their content into two classes: Negative or Positive.

Let me give you an example: I've read this book with much expectation, it was very boring all through out the book
The answer to this example can be: Negative
Here is why: Review writer does not like the book because it was boring, therefore it is a negative review.

OK. solve this:
It is extremely rare to see so many world famous super artists performing together in the same concert doing some of their greatest hits - Elton John, Sting, Mark Knofler, Carl Perkin, Eric Clapton, Paul McCartney, Phil Colins etc. You must own this DVD before it is out of stock. I would have given it 5 stars should the audio recording be slightly better. Go and buy this one with confidence. I am sure you will not regret.
Answer:
Positive