Get the best you can afford - you will be amazed at what you can see
with these things. And get the low light option.
Good luck - have fun.
Later,
I have an AquaVu and it is really fun. One caveat for this application.
The lens is pretty wide angle which makes sense considering the relatively
low visibility conditions in most fresh water. So depending on how far back
you run the lures and how fast you troll, it might be hard to see much.
They work in air also so you can get an idea of what stuff would look like.