I have purchased quite a lot of photo equipment from KEH over the years and have never had a problem.
If I know it will be a month or more before I use the equipment, then the batteries come out. I had an unfortunate incident once that made a strong impression on me.
I shot with film for years. Wildlife and landscape for the most. I used a Canon 1V for wildlife and birds in flight. Canon 100-400 L series.
I later went to the Canon 1D Mark 11 and have no regrets. The camera has the same feel in my hands as the 1V, and yes it is heavy, but so is the 1V, and the Mark 11 will do the same job and better in many situations.
The Great Smokey Mountains National Park is one of my favorite places to do photography. Snow scenes are my favorite, and next would be the elk in Cataloochee Cove in the eastern end of the park. I have a lot of 20x20 enlargements, All done on film, so I cannot post here. I am just starting in digital with a EOS 1D mark II.