I want to start off saying that I think this is appropriate for almost any age. My son got this for Christmas and he loves finding change to put in it. He tried to have more money that his sister. It is a digital counting bank and all you do is put the money in. It reads the change that you put in and tells you what the amount of the coin was that you put in and then it tells you the total of the money that you put in. We love this because all you have to do is look at the top of the jar and my son knows how much money is in it. To reset it you just unscrew the lid and on the bottom you will poke a pencil in the small hole.
The only downfall that I see, and it really drives me crazy, is that if you don't put the coin in just right it will read it even though you didn't put it all the way in. What I mean is, say you put it on the slot but don't have your fingers on it just right so it doesn't go all the way in. It will read that you put that coin in even though you didn't. So your bank will be off by however much that was unless you reset it and add all the change all over again.
I think this could be fun and educational for your children. It will teach them how to save money as well as the value of the coins they put in.