I don't even use 4g now. Battery suck. H+ is good enough for me.
No skin off your nose either way then. :)
Unless your device is using a really poorly optimised radio baseband stack, though, 4G should be better for battery life than 3G these days. Can wake up, fetch data faster, and go back to sleep faster, plus the signalling from the towers (To sleep/wake/sustain traffic throughput) is much improved in 4G-land. Actual radio engineers can explain the air interfaces much better than I, but suffice to say unless you get rubbish 4G signal - or as previously mentioned have a device with a dodgily-configured radio - 4G really is better tech.
Worth noting that tuning for NZ networks is part of the background optimisation/certification process all devices sold through NZ telcos go through, and using a parallel imported device on international firmware side by side with a local model can demonstrate surprising results in favour of the latter. There will be more and more reason to buy local in the years to come, and I say that working for a business that sells a lot of international models which aren't served to NZ through operator channels.