I upgraded my Lumia 920 (AT&T). It actually seems more solid than the 950, as far as the OS goes. The 950 beats it hands down on features, the 920 wins on OS compatibility and style.
That all being said, the 950 is now on build .63, and gets about 28 - 30 hours per charge. The 920 is already on build .71, and thinks it will get 48+ hours (just took it off the charger to test).
I really miss the rolled edges and the curved glass of the old Lumias, but I have to admit they can be easy to drop. The 950 is a lot easier to hold on to, as boring as the design is. A MOZO case helps, but the shape is still pretty anonymous. Hardware features, though: unbeatable.