What we've seen so far are not data points. There's too much speculation involved, and the picture isn't nearly clear enough to call them that. It may seem like a game of semantics, but how to filter out the noise in order to learn what's really going on with this stuff is an essential skill for anyone who's more interested in the technology than they are the drama which goes with it.
As for the OPs question, I'll second DancinJack and say get the 1080Ti. I wouldn't consider anything below that a worthwhile upgrade for the amount you'll be spending. To be completely honest I wouldn't upgrade at all, but if you plan for this to be your next GPU for the foreseeable future the 1080Ti is the one I'd pick while the pickings are good.