basically they're left-neoliberal.
substantially better than National, but their record in government has been disappointing and there are worrying signs it's not likely to move to the left after today's win.
the prior Labour government (lead by Helen Clark from 1999-2008) was much more impressive in its historical moment. Again neoliberal, but did a lot more of interest - renationalized air new zealand and the railways, created a state owned bank, set up a proper tax credits system ("tax credits" being a weird name for a form of low income welfare), improved health, kept out of iraq, slashed rents in state owned housing, and improved labour and union rights, etc. it was still neoliberal in macroeconomic management, but it's probably the only leftish party that actually made a lasting positive impact by being in government during that period. (contrast Britain's New Labour and the German SPD, who fucked up way more than they fixed.)
basically, the party doesn't deserve uncritical support and they've been a disappointment this time around even given the historical moment, but the uncritical loathing they'll no doubt attract from certain kinds of /leftypol/ user is misguided and overlooks the potential for a far more interesting analysis of the options and limitations available to electoralists.
NZ is one of the safest locations in the world, which perversely makes it very strategically important. Half of silicon valley wants to buy a bunker there in case something happens in the US.
Plus in the more extreme climate change scenarios NZ remains habitable while Antarctica gets opened up, with NZ being one of the last stopping points en-route on that side of the world.