I always leave my Note 2 on LTE (no Wi-Fi ever) and get great battery life (currently at 3 days, 6 hours with 2 hours screen on time; see screen shot below). From my experience with my Thunderbolt and now the Note 2, LTE itself is not a major battery drain, it's much more about the signal strength and how hard the phone has to work to hold onto it and how that may cause it to frequently switch between LTE, 3G or even 1x. Although admittedly, the newer generation radios such as in the Note 2 are much more efficient than the first gen. Thunderbolt were, so there is a contributing factor there.

In my case, where I live LTE is strong so the phone is always locked on to it. Otherwise, when I do use the Note 2 heavily (again on LTE), I still get a whole day of use (ex. 20+ hours with 4-6 hours of screen on time). It takes a lot to kill the Note 2's battery!
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