So I upgraded to LTE... my verdict, was it worth it? Probably not.
There's about 2x boost in map tile painting, but still, that's not instant or anything, you still watch them block in. When you add in earth view and traffic, you start to notice the difference in speed more - for the better, of course. Sometimes the map tiles slowness to arrive seems to be a server side constraint, and not a transmit constraint. So LTE at these times is "a waste" because 3G waits just as fast, if you know what I'm saying.
And Slacker songs load a bit quicker when skipping to next. But they start playing before fully loaded anyway, so what if the rest of the song you haven't heard yet loads faster in the background?
My trip between cities I am most often traveling between all had good LTE coverage, but they also have good 3G coverage too. Never get into a dark zone with either.
I notice I am usually on 1bar LTE sometimes 2, rarely higher than that. 3G seemed to show 2 or 3 bars mostly all the time.
I might receive firmware and map updates and download them quicker, at LTE speed, but again, so what?
Overall, save your money, it's not that big of a user experience difference to justify the cost.