I recently purchased a Brunton Eterna 6x30 Monocular for use in my kayak, as I was looking for something smaller(and cheaper) than my binoculars. They are perfect for their intended use, spotting things at a distance. The optics are crystal clear, unlike the view one gets looking through a cheap pair of binoculars. It is fairly lightweight and will fit in PFD pockets, and is easy to hold steady in a boat due to the 6 power magnification. For this purpose, it gets a ten.
What I did find, though, is that it is not as good as binoculars for actually studying wildlife, so if that is your purpose, you will probably not care for it.
