I love both, but my "environmental" preference is for rivers. I don't know a thing about your fisheries, but to me, stillwaters can seem a little unnatural. there is always a building nearby, or some other people, unless you have a very remote and secretive stillwater location. Rivers tend to be a little more natural, and there can be little to beat a wild trout stream in a pristine and picturesque environment. To me a single wild rainbow or brown, taken from a clear cold stream, beats a thousand stockies from an artificial lake. That's just me, I'm a "wild and wonderfull" snob....sorry