Driving - best offline / online GPS navigation mobile app or buy a GPS device ?

Dear everyone

I would like to know if you are familiar with any online / offline GPS android app best for NZ?

Google maps may be good, but how about the 3g/4g connectivity through out the road / state highways? Is it reliable to go for an online app?

I have another app call Map Factor , which uses OpenStreetMap ( OSM). As I have not used it in NZ, I do not know the coverage and accuracy.

Should I buy a GPS device specifically set for NZ? I am currently in Singapore, and should I buy a Garmin GPS device from here itself and set it up ready? As I am renting a car from Palmy airport, I wanted to make sure my first drive itself goes smooth on the road.

I would like to hear your suggestions.

Thank you.

I got this one https://help.here.com/android/maps/#q1621
Installed it, trying it in Singapore. Seems to be a good offline map

The car hire company may rent them out - it's worth asking.

Get yourself a road map, a good old paper one. We've driven all round New Zealand, up to Cape Reinga and down to Bluff with a map. It's not that complicated.

We pretty much use google maps on the phone. There are places where 3G/4G is unavailable, but in those places the road options are so limited we've never lost our way. We're just sure to review the route when we start out so we have a general idea of where we're headed before our next stop. You might be surprised how few roadways there are actually are between places :)

Thanks Jandm, Car rental company said they don't have one for the day.

can I get a full traditional NZ map at any NZ airport?
I tried printing but cannot find a proper hi resolution map with all the locations marked. I can print it out on an A3 sheet if i have a map

I guess online maps will cost too much on mobile data . is it not?

Mobile data is generally pretty economical and online maps don't use much. It's all personal preference / opinion I guess, but I think if you get a local sim with 1GB of data you should be good to go.

Ok thank you.
I guess I can get a SIM in Auckland airport itself.