I like how easy it was to use because you don't have any ads or popups when using this program! You can search stores by location so if your looking in San Diego there are many options around us but not all over California (like Groupon).
If you're thinking about signing up with doh make sure they offer as much as possible first before committing otherwise i would say wait until more promotions come along. We've been able to save $50-$100 per month without realizing since we were only getting 1-2% from our spending habits.