Welcome to the forum, and congrats on the job offer!
I'm on North Island, and not a rider, so not really sure about the areas. (the only one I've been to is Christchurch, and really only in the city...)
However, on the basis of you having a job offer in Gisbourne, I *really* would recommend that you go for that first off. When you are settled, then you can take a look at the other areas, but jobs are not easy to come by at the moment (speaking as someone who had a job offer and then lost it before I started!
), and it would be better to end up somewhere that is slightly less than perfect and re-build the cash from the move (do *not* underestimate how expensive it is!) and take it a bit slower...