Capture One Pro is on sale right now for almost the same cost as the camera dedicated versions. Check that out here at B&H photo. You could buy this now and have support for all the different brands, but keep in mind Capture One does make you pay for future updates. So you might have to spend a little money in the future to unlock the upcoming Nikon profiles and support. But maybe not.
All you hear about is how much better Capture One is than Lightroom, but is this true for every brand of camera? Does capture one handle X-Trans better and are Capture One's colors better? I will summarize since I can't get too deep into all the features of each program in a written review, it would take forever, but mainly we are going to look at some straight out of camera samples.