I own ResellerRatings.
Many people who post there are there to complain.
I hear that all the time but it's not really accurate. As of this posting date, 73% of all survey responses across all stores are either "Somewhat Satisfied" or "Very Satisfied". Only 27% of respondents answered, "Neither Satisfied or Dissatisfied", "Dissatisfied", or "Very Dissatisfied". Note that the top 45 stores have overwhelmingly positive reviews:
http://www.resellerratings.com/topstores.pl
The reason some larger stores like Dell, Buy.com, Amazon, may be poorly rated, is because ResellerRatings attracts a power user/demanding audience, one that expects personalized top notch prices, service, RMA policies etc, that the big sites don't always provide, and also these users tend to buy more often from the Neweggs/Crucials/medium to small stores, which means a larger volume of reviews for those stores as well.
In regards to another comment, stores are permitted to solicit feedback from their customers in exchange for discounts on future orders etc, but any such offers must only request "feedback", not "positive feedback", and the offers must be honored even if the store receives a negative review. Users do report stores to us that violate this policy, and we take action against stores that do (like disabling any reviews that were solicited improperly, for instance).
We also do everything we can to detect and prevent fraudulent reviews. If we detect that a store is submitting fake reviews for itself, we'll disable the reviews and warn the store. A second offense gets a public note added to their reviews page for 30 days, and a third offense makes that note permanent with the possibility of disallowing any future reviews for that store.
So, is ResellerRatings accurate? I think so. It's the best there is, IMO. You still have to use your own judgement, read reviews, look at ratings, and always always always use a credit card when shopping online to be almost universally protected from fraud in a worst case scenario.
And BTW, about 1,500 merchants actively monitor their reviews at ResellerRatings. We routinely get people thanking us because a merchant contacted them and corrected problems after the merchant read their review at ResellerRatings. So, the site can be a catalyst to help with any customer service issues, though we always recommend contacting the merchant directly to resolve any issues.