My credit union actually recommended them. They are legit, but do not have the personal customer service as some of the smaller reward sites. It is a trade off. Higher % back at Ebates, but they don't need to keep you happy to stay in business.
I have had an account for years. I usually only use them if the merchant is not available on Sunshine Reward or if they have a very high cash back promo. Black Friday and Cyber Monday are awesome!