I've been following this with interest and am not surprised at the amount of different experiences and opinions. I think alot depends on what you are leaving, what you are looking for and your expectations before you arrive.
We live 30-40 mins south of Auckland off peak (1-1.5 hours peak traffic and more since they put the stupid airport motorway link onto SH1!!!) The ds's go to a rural school with 100 students, 5 classes so approx 20 students per class - decile 9 and approx $300/year although over 50% didn't pay last year! It's been great. However, ds1 will go to a private intermediate and high school (he starts next week). We are zoned for very dodgy south Auckland high schools (by a few hundred metres) and can't get into the decent ones for love nor money. Also not convinced by NCEA (controversial I know) and he'll do Cambridge exams.
I find food expensive but we grow as much as we can, have chooks and the poor lambs end up in the freezer. I also think housing can be expensive depending on where you choose to live - we are looking at moving further out.
We enjoy a great lifestyle but dh earns a good salary, we did very well with the exchange rate when we moved here 8 years ago and I work too but I am able to work around the boys, school and sport. We have a bach (beach house) in a small place on the west coast an hour away - it's like going back in time and it's great. We've just spent a month there over Christmas. If we didn't have to work we would just live there. There really is no local work and not in my field anyway.
I agree there is no keeping up the Jones' where I am, the ds's do not wear shoes to school, have hand me down uniforms (everybody just passes them on when the don't fit), don't have the latest gadgets etc... It is far easier to entertain them on a shoestring than in the UK - our swimming pools are free, sport registration $25 per season, beaches, parks etc all free - we get out the bikes, boogie boards and go.
I did however find it hard to make friends - not sure why - could be me 
The downside - distance from family, the cost of international travel, lack of different cultures on your doorstep (I know NZ is bi-cultural/multicultural especially Auckland) but I mean being able to hop on a plane for an hour or two and be immersed in a completely different culture/language/architecture etc....(we have yet to be able to afford New Caledonia or Tahiti
).
Like everywhere and everything it will be what you make of it.
Tauranga is great btw.