A few things to consider:
-The exchange rate was great a couple of years ago, but now the NZD seems to float between 0.75 and 0.80 USD, which makes a difference of a few thousand $$ depending on when you pay tuition! However, it is nice that it's grandfathered (I think) so the amount in NZD doesn't change once you enter the program.
-The cost of living in Palmerston is definitely pretty reasonable, as the previous post said you can share for pretty cheap or get a place by yourself for about $400-$450 US/month. All the extras, phone/internet/HEAT add up though, so that's one downside of not having roommates to split it with. Probably cheaper than Edinburgh, and maybe it makes up for the difference in flight costs to go home.
-Vehicles are pretty affordable here, just get something with good fuel economy as gas is more than we're used to paying for at home, however it's not like you end up driving a ton.
- Activities outside of school: reasonably accessible. Remember, most vet schools tend to be close to farmlandy areas, which generally aren't known for their recreation opportunities, so PN is probably about average. And I don't know about other folks, but I tend to have spend lots of time studying on weekends!
-The climate here is really moderate. It occasionally freezes overnight in the dead of winter, we never have snow, but there are a few months of the year where it is very grey and damp for long stretches of time. I miss the seasonality that you might get more of in Edinburgh, but on the other hand it's very easy to get around etc. all year here but it seems very bland weather-wise. Although I am watching it pour rain right now, we have just finished nearly six weeks of stellar weather, and I think have worn shorts to school almost every day since school started at the end of February.
I applied to Massey and got in right away, so I never caught one of the regular application cycles for the UK schools once I had found out about the AVMA schools outside of N.America, plus everyone I knew who had been to NZ had loved it (note: they spent most of their time on the south island!).
Things I think would be better going to Edinburgh:
-cheaper flights home
-if you plan to go back home for the summer break, at least you get summer rather than being on the perma-winter plan like we are.
-easier to bring pets
-more summer work opportunities since you would be in sync with the school year in N. America
Remember, there are worse decisions to have to make than having two great opportunities in front of you. There are things that frustrate me here, but I am overall happy to be at vet school and I think it is really what you make of it.