I've only had it a couple of weeks. I have a 5DmII that I shot a lot of frames with but it has been on loan to my brother for a few years, my photographic activity has been way down. But I missed it too much to stay away... I had a short unsatisfying flirtation with some Olympus gear as i was trying to find a camera I could carry more comfortably while hiking. But there is so much more to a good hiking camera than size! Image quality really does matter...
I love that the 5DSR is so similar to the 5Dmii, and the quality bump is amazing. The 5DSR is more demanding of technique. I'll probably find a carry lens with IS, but my existing lenses are working just fine with it. It is a bit noisy at high iso But the great majority of my work is off a tripod so that is no big deal...