It is still king......that is until Samsung outdoes itself with the 960pro (soon to come). It only offers very marginal improvements over the 950 though, so wouldn't find it worth the wait at all.
I will throw out though that that the perceptible difference that you'll experience going from a good SSD boot drive (say a 850Evo) to a NVMe PCIe drive as your booter will be practically nil, as the difference in speed is all down to fractions of a second.
Anyway, just consider it. As you can buy lots more size with the same money now, and unless you're doing NVMe to NVMe transfers (which is brilliantly fast), then it looses some of its cache.