The 2016 OLED's really took a nice step forward in near-black performance, UHD/WCG/HDR calibration, and I would expect by 2018 or so, they will be brighter and even more polished.
They seem to have advanced a little faster than plasma on that side of the ball, especially calibration, but the knowledge was already there from plasma and LCD. I'm not sure when the price will be what a 65" plasma was at launch ($3500), but I don't have one regret about what I spent on my 2015 65". If the 2017's continue to polish and perform well, I will probably look at one of them in late '17 when they are getting nice discounts, depending how their WCG performance is.
The 2015's have limited HDR/WCG calibration options.