Ohau is great, especially if they have fresh snow. The mountain road is pretty sketchy though, especially if its had snow. Friends of ours got caught in an avalance on it a couple years ago.
There's one lift which is ridiculously slow but if you hike to the top and round the ridges theres some great terrain and its usually fairly untracked. Unless there getting fresh snow I wouldn't look to spend more than three days there. I can't remember but I think eftpos services up the mountain might be limited or non existant so I'd look to take cash up. The hotel at the bottom of the hill is great with a sweet restaurant/bar and spa pool for relaxing afterwards. Also get some Tiki tour groups going through there so can be quite the party cranking but usually pretty mellow.
All in all I've only had good experiences there and there's enough to keep you busy for a couple days though you might have to get creative with some things...but thats the best way to progress aint it?