I haven't made the jump to Windows 10 yet - I'm probably going to wait until November or so, just to give them a few months to iron things out.
Remote Play on PS4 has been pretty impressive in my limited experience with it, which has pretty much been using it twice - once to demonstrate how cool my Xperia Z3 was, and once to demonstrate how cool my PS4 was. The small screen really takes something away from the experience though - a tablet would be the way to go, but I don't think I want to buy one just for Remote Play...
I guess I should amend my question to: How is Xbox One/Windows 10 streaming as compared to PS4 Remote Play?
Since I would be using them for the same purpose - playing games when other people want the TV. The projector Sony showed off at Gamescom is looking more and more like what I would want, since it bypasses all the wireless issues. Too bad it's going to be expensive.