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:
We have 3 of these Lux systems in our sprawling house. All 3 have in a few short years had the LCD screens become unusable at night with the incorporated light. The programming part works well enough, The LCD is ok in a well-lit area, but we need to use a flashlight every time we want to adjust them. Not surprisingly, we adjust them less often. It is very frustrating and seriously compromises and otherwise good product.
Answer:
Negative