They are the coolest thing since sliced bread. Not only do you save so much money when you buy them, they are so compact, you don't need a lot of room for storage. You get multiple dies in one package, so you don't need to go out and get a separate punch for every size. Myself, I waited till I got a coupon for the store I bought them from, and then purchased them. Joann's website also has them online for a really good deal. All in all, you spend about the same.
There are a couple of dies I still need to get, like all the square ones. After that I think I am just about covered as far as the dies that I will use the most.