Well, I've had my 650 for two weeks and have been putting it through it's paces. So far it has proved to be a learning experience, after having used an etrex,Dakota,and Oregon. I don't know if anyone has tested the "Water Proof" feature of their new Montana, but I thought some might find it reassuring to know that I have tested it and found it to be VERY effective!! I dropped it out of my canoe this week while shooting some rapids. I wasn't able to get stopped and back to the spot where I lost it for about 15 minutes. The river was very clear and I was able to find the GPS sitting in about two feet of water on top of some rocks. When I fished it out it was still working fine, and had even taken a picture of the sky above the water when it landed.