KenB - 6:46 pm on Feb 25, 2010 (gmt 0)
I also find "negative" reviews that are constructively written valuable in better understanding the product I'm going to buy. They don't necessarily stop me from buying the product, rather they help me know shortcomings of the product and allow me to manage my expectations. I especially like "negative" reviews that provide a workaround to a shortcoming of a product.
In the end, negative reviews can actually help me be happier with a product because I already know about its shortcomings ahead of time and thus wasn't disappointed to find something not as I expected.
If I see an nonconstructive "slander" type review I tend to ignore them as someone with an axe to grind unless I see a pattern of negative reviews.