I would second the leica. I have a leupold and find it works in brown conditions well, but snow really affects the range reading. The leica I have tried did not seem to care...but thats where you get what you pay for comes into play.
I here ya cowboy on the guestimating. I only got a rangefinder because it seemed in the woods I could not guess as well as at an open range. So the first time I used it, I still missed!!! Hahaha. Killed a big rock though...stopped it dead in its tracks while the deer ran off.
i do like to practice guessing with it every season. I guess then range. It helps me get rock solid as animals never seem to come in or stop next to the bushes or rocks you take time to mark out.