I traded a Canon EF 16-35/2.8L II, toward the purchase of a pre-owned Nikkor 70-200/2.8G VR. I had bought both the 16-35/2.8L II, and a Nikkor 14-24/2.8G, last year, and had figured I would keep the one I favored, a probably trade the other. Well, a bit over a year later, it is done.
I can still shoot ultra-wide, on Canon, when needed, with an EF-S 10-22mm on a 7D or 7D Mark II. My widest EF lens, for full-35mm-format frame Canon, is a 24-105/4L lens, which I rarely shoot wider than 28mm. I seem prefer Nikon when shooting wider than 28mm.
Canon 5Ds R/7D2/7D/5D/40D/1D2N; Nikon F6/D3s/D700/FM3A/Coolpix A. Lens selection undergoing changes; some favorites: Zeiss 2/135 APO Sonnar, Canon 100mm f/2.8L Macro IS and 135L, Nikkor 14-24/2.8G and 200/2 VR.