My experiences with online reviews have been great, especially compared to anything a big box store can offer. With the help of websites explaining the technical details, forums discussing the product, and reviews at places like Newegg and Amazon, I am armed with much better information that I would have been had I gone to Best Buy to look at something and asked an employee there.

I can even look at manufacturer responses to reviews on Newegg, and ask other customers about specific issues I might have with a product. Of course, there is a possibility of the system being gamed, but I've had nothing but great experiences, although I am still vigilant for manipulated reviews.

Edit: I also don't have to choose from substandard consumer products sold at most stores, with high markups on trivial things like wires. With monoprice, Amazon, newegg, and others I can get reliable, quality products for what they're actually worth.