I do, but its limited on boost anyways, plus as I understand it, 4g significantly drains the battery, so I may just use 3g and be done with it, and use 4g in dire emergency situations.
I've never been disappointed in 3g myself, considering you will only connect as fast as the other side will allow anyways, so if the other side is say on a 56k speed, you will only ge 56k speed. On top of that there are many variables to factor in as well, such as weather, so 3g isn't that bad to me really. Also 3g is a lot more saturated in more areas than 4g is.
Don't get me wrong, 4g is nice, but if you've never been on a14.4 or a 56k connections, you tend to appreciate 3g for what it is. We seem to quickly forget what we once had to use then get spoiled on all the nicer things, then we are quick to complain.