I used it while deployed and it was great for that time in my life.
I decided it wouldn't work here in the states b/c I carry more than 3 cards at a time (usually at least 2 ID's, 2 credit cards, and various other things like temple recommend, frequent buyer cards for grocery, etc.) and it doesn't allow for carrying cash.
I guess it comes down to what you like to have handy on you at any given time. It was nice having to carry just one thing in my pocket.