I'll offer an American view to the OP.

My family and I (wife & 2 school age children, 1 with mild special needs) looked into relocating to NZ late last year. We chose not to go. We made an exploratory trip to NZ before we made our decision, and this was our experience:

Income and Expenses - I cannot speak to obtaining general or trades employment in NZ. My wife and I are both professional types with doctorates, and we found that (a) the employment situation was bad and getting worse and (b) that we would have to be willing to accept at least a 30% paycut, even taking the exchange rate into account. Earning less is fine, so long as expenses are also less. They aren't. Again, I cannot speak to the cost of living in UK or Europe, but costs compared to the US were out-of-this-world. We found, easily, groceries costing double what they do here, with many things more than that. Utilities were far more expensive in NZ than here. Petrol, phone, etc. - all more expensive. My family is not overly-materialistic, but that was far more than we expected. I would also say that the current attitude towards recent expats and work has worsened significantly - read this: NZ 'paradise' not so wonderful for British expats, says UK newspaper - National - NZ Herald News

Housing - in all fairness, housing in NZ is a national scandal. Building codes either don't exist or aren't enforced at all. The mold problem was quite high, with little thought to insulation or water-proofing. The general state of housing in NZ would make a US building inspector head straight to the courthouse to sue whomever built it. It is also much more expensive than the US, but it would appear to be in line with European costs.

Medical care - for all the talk of "socialized medicine" being better than the US system, I found it to be totally untrue. There are waits for doctors. There is rationing. We don't have either in the US, but we do pay for our system. I guess it's just a choice of what you're willing to put up with.

Education - we looked at schools for our children, and I found a dire lack of special education resources for my one child, and there really wasn't a lot of "advanced" educational opportunities for my other child - one needs lots of help, the other is exceptionally bright. Both ends of the spectrum was a letdown.

Social - crime is far worse, per capita, than in most places in the US. NZ has a lot of gang issues, and the police appears to be behind-the-curve on this issue. We also experienced a definite anti-US bias while we were there, and it wasn't looking to get better. Perhaps this is better with Brits, but US expats have real issues there.

All-in-all, we decided not to go. Everyone will have a different experience, but that was ours. Good luck.