they do work the draw back is price, i make my own blocks that work just as good but at a third the cost.

Sure,
1- large jar peanut butter. (softened in micro)
2- 1 cup Brown sugar
3- 3 cups Corn Meal
4- 3 cups Rolled Oats (Quaker Oats)
5- 2 tlb spoons vanilla extract( real not synthetic)
6- syrup ( cheap stuff)
7- 2 cups corn

combine all except syrup into a mixer bowl and mix until everything is mixed very well.
them begin adding syrup until mix gets thick. be careful not to add too much, mix will end up like a brick if you add too much syrup.
pack mix into an old butter tub and let stand overnight, when ready to use mix will come out of container with litter effort.
sometimes i add fruit just to mix up the taste.
if you get quantity on all items you can make a bunch of bricks for very little cost per brick.
and the deer love em!!!!