I'm hooked on a two-body system, in the 1Dx and 5D lines. Having both available when I'm photographing a grizzly is a very happy time. I tend to upgrade sooner than I should (early adopter syndrome), but I never regret it. Even though the next upgrade is a few years away, I'm excited to see what it will be. With Nikon's new D850 out on the market, they've really raised the bar and I'm sure Canon will do their best to leap over it.