To anyone starting out with night vision it really has become a problem. The market is changing so quickly, what do you do? When I got my first nv I thought it was marvellous, now I don't! My night vision set up that I use now is brilliant, but I bet it won't be too long before something supercedes it. If you get something that works now, use it and be happy! Get the best you can afford but try it out first.
As someone has said, you really don't need to be shooting foxes out to 200 yards, the whole purpose of decent night vision is stealth. Over the years I have kept a record of the distances foxes have been shot at and it always ends up around 100 yards average. Most half decent nv equipment will allow you to shoot a fox out to 150 yards.