Bullcat,
I have used nightvision a few times now when hunting. It's great for sitting in the dark in the middle of a field, and quietly scanning for pigs. Then when you are know they are there, hit the spottie and go for it.
You get what you pay for. Gen 1 or 1+ is useless for anything except seeing where you are walking. Personally I wouldn't buy anything less than Gen 3 or 3+, but you are talking big dollars. I'm not sure whether 3 and 3+ are still restricted in Australia (to LE/Military), but it's the way to go. Add in an IR torch (invisible to us humans) and the range is easily 500m+.
On a side note, I have used thermal imagers a few times as well (not while shooting). It is truly amazing how much wildlife is about at night in our beautiful country. Many times I have sat on a hill and watches literally hundreds of kangaroos, rabbits and foxes that had no idea I was there!
Personally, I would avoid NVT.com, they tend to sell older, cheap tech.
Just my opinion.
Cheers,
700.