You can use it here fine (I have one) but be aware:

• If you want to access the US Prime offerings you will need a DNS (Amazon Video will work for NZ offerings)
• It does not have access to the Google Play store (You have to use Amazons app store) or any NZ Specific apps (E.g. TVNZ on demand, Three, Lightbox, Stuff, NZ Herald, NZ Banking aps Etc.) (You will have to side load any you want)
• It runs Amazon's own Android version - heavily modified from standard Android.

Hmmm thats a tough one. The lenovo all round is probably the better buy as I can just use amazon prime on it and get the benefits of chromium. Just the Fire 10 looks nice, but so does the Asus, its real eye candy but surprisingly the screen isnt so bright.

I considered a Surface Pro 3 or similar price, as what I really want is a bedroom ultra light notebook, but figured a tablet can do all I need it to, google, youtube, netflix, prime etc.........

A surface pro 3 will set me back about $600 used with keyboard and pen, plus I can use a mouse, you cant use a mouse on the tablets right? I can use a BT keyboard and just touch instead of mouse I guess and its a lot cheaper option.

I think I saw the Lenovo 10 on sale for $300, but have seen them for $200 used.