It really depends on which way you want to go. There are definitely meals on the menu that are under the voucher amount, but if you get the more expensive meals there is definitely more of a value (and luxury.)
Another thing you need to add in is the tax and tip (which are included in the vouchers.) This can add up, as I'm sure you're aware.
Also, if your kids are older, they will likely eat the whole kids meal. It seems older kids eat like it's their last meal, when it's at a restaurant. My kids are 2 and 8. I ate some of my 8 year olds entree, some of my husband's. The 2 year old ate some of everything. We ate family style.
Also, ask the advice of your server. They are eager to help because their tip is built in. Actually, they fare better when a more expensive meal is purchased.
We went ahead and ordered an extra drink and appetizer (unnecessary) and were always STUFFED.
All this really hinges on the age/appetite of your children. The Lunch Vouchers are a very good savings. The Quick and Casual are not as great, but it is still nice to pre-pay for the meal and forego paying tax.
Hope this helped. Hotwire also had some pretty good gift cards too, and cancelling wasn't a problem (Iwas worried about getting ripped off.) Seems it is a normal, up-and-up company.