My answer is - YES! This is what I got in my mailbox yesterday, a $10 check from Kraft from their buy $30 get $10 back and a $7.99 from Schick, which equates to about a $4 money maker! When I bought the razor it was $7.99, but I used a $4 coupon. I still got the entire $7.99 back as a rebate check!
In order to stay organized, as soon as I purchase the items on a rebate, I fill out the form, clip the UPC(s) and mail them with the reciept as soon as I get home from the store. This way I do not forget them. I think it is totally worth it! 6-8 weeks later, instant money in my mailbox!