Without any other changes in locations of use or WiFi availability/use, despite playing more with the phone since getting the iPhone 5 (after all it's a new phone, had to get apps on it, play around more to try things out and enjoy it), even with the ability to use LTE now, I've actually used around half as much cellular data as I have on average in previous months with an iPhone 4 (limited to 3G, when it comes to cellular).
Will that be the same next month...hard to say. But that goes to show you that it truly does come down to being an individual thing, and LTE or not it still can (and will) be different for different people at different times in different places.