Yes, I have had some experience with them.
Look at the coupons in the booklet, find some that you know are "real" and ring them up and ask for more info.
Generally coupon books are a way for businesses to stimulate new customers by using the quieter times of the week to offer cheap deals.
Almost all coupons have restrictions on them, restaurants are almost always week nights or early sittings, hairdressers are Monday, Tuesday, etc etc.
As long as the people selling the book deliver the book it is then up to the traders to honour them correctly.
Add up the coupons you think you will use and see if there is a saving there for you.
We got our moneys worth easily but we were happy to work in with the traders restrictions to do so but you do need to be aware of the time limits on the coupons.