If you have the tablet mostly in NZ, it is not much point to have a Sim card equipped version

But if traveling in foreign, it may be worth it.
For me, when ever I hit a country, first thing is to grab a Sim card and stick into the S3Tablet and off I go.

1. Much cheaper to use local sim card for data
2. Quite a number of countries I go, have no data pack you can purchase for NZ sim card, eg 2Degrees Aust pack
3. Tethering to a phone has lag for me in time critical data, eg Skype/Hangout etc
4. Got fedup in trying to replace my NZ sim card with local sim card on my phone in each country.
5. It is worth maybe $200 more to have sim version, not much compare to what the thing is worth.

Point #5 is what push me towards Sim version.
You will be wondering forever if a sim version will work better for you.
Where else, I can run around in a sim version without a card in it, and it still works.