I'm paying for the 3 gig for $30 plan via AT&T. I am out of town in an area with super slow wifi so I have been using the data most of the time. By using data mostly, but still only downloading apps on my computer and transfering them.. I am using about 100-150mb a day. If I lived here, I would definitly go through 3 gigs in less than 30 days.
But where I normally live, I have fast wifi at home and fast wifi at school and both places are where I spend most of my time. I'm not even worried about using a bunch of data here where I'm at now because I know I won't use very much at all where I normally live.
I'm not worried about it... I love my ability to go online with my iPad almost anywhere. And yes.. the LTE is blazingly fast and awesome!
As long as I don't download or stream using my data connection, I'll be fine.