There are a lot of great coupon sites out there but Shopathome is the best one I've found for Cash Back and many times has the same or better coupons with ability to also provide cash-back... something retailmenot and others don't do.
Here's my top pros and cons of Shopathome:
Pros
110% Price Guarantee - this is a link available on all stores that offer cash-back. Every once in a while I'll find another site offering better cash-back on a store I'm going to purchase and never had a problem with ShopAtHome honering at 110% better cash-back price
Earn cash-back on everyday essentials - ie, I buy everything from toilet paper to toothpaste on shopathome and pickup at Walmart or have it shipped from Walgreens or Drugstore.com and save lots of money + earn cash back.
Cash-back often works with coupons as guaranteed on each of their store pages to double dip on savings.
Use for travel! Most travel sites don't offer a lot of coupons but Shopathome guarantees cash-back at 110% on everything from hotels to vacation packages... if you're already booking your hotel online, great to have cash-back on it as well!
Responsive customer service - other reviewers seem to have an issue but I usually get an email response within about 2 business days on the 2 commissions I have had
Toolbar allows you to see cash-back anywhere you are shopping online
Every day they offer a good cash-back deal on a product or store that is much better than I've seen on other sites
When you search for a product in the search box it will show you cash back options for that specific product as well
Cons
Cash-back isn't paid till $20 is reached - eBates is similar but sites like big crumbs is lower
No PayPal Option
They push their toolbar a lot - personally don't like toolbars and wish it would stop asking me.
Need to pay attention to the cash back guidelines at each store page to make sure your purchase is not restricted... ie, gift cards, iphones, and some categories might have lower cash-back rates
Have found some of the coupons other sites are offering can be higher than what Shopathome has with cash-back... seem to net out in the end in most cases but wish shopathome always had the best coupons