The problem with night vision is the lack of colour differentiation - I couldn't imagine trying to find a toad in a pond in a field in the middle of nowhere if I couldn't see the colours :/.
I can understand this issue to an extent. I suspect I am a bit spoiled from all those months standing "mine watch" while underway in the Persian Gulf has spoiled me.
Many, many folks have trouble with the limited depth perception of night vison also. I find that these civilian active emission models work pretty well for animals, as the retina reflections stand out like a flare. With true passive emmision systems, something as simple as moonlight can really render them hard to use. While in the canoe, it makes navigating much easier on the eyes and provides a better field of view than a spotlight or head lamp.
Truth is, I really enjoy the reactions I get when I stumble across fisherman at night and they see a scawny looking fellow dragging around all sorts of strange gear, none of it for fishing.
By the way John, thanks for the headlamp suggestion, I picked one up and it is brilliant, literally. I find it usefull for night herping and boating, and excellent when crawling through a greasy set of machine guts at work.