I've enjoyed AT&T unlimited since day one of iPad 1's 3G model and am still loving it. I plan to keep it till they cut me off, lol.
For me, owning lots of devices is a treat. I don't see need to justify my uses or enjoyment to anyone else unless they care to pay all my expenses, lol.
I find that when other people try to mind other people's spending, it's usually a case of sour grapes, or of them not having enough money of their own to mind, lol.