I have this same Dell Insp 7559 laptop - picked up much cheaper over a year ago as a refurb direct from Dell - paste of the slickdeals thread if woot allows those: https://slickdeals.net/e/10228316-dell-outlet-dell-inspiron-15-7559-laptop-refurb-545-3840x2160-touchscreen-i7-6700hq-8gb-ddr3-1tb-hdd-gtx-960m-4gb-win-10
4K screen is nice, even though windows 10 still likes to pop up some windows with tiny fonts. I like having a touchscreen although I don’t use it as much as I would’ve thought. The 960m has been good enough for my Steam backlog (thank you humble bundle). I don’t use highest settings and haven’t played a lot of recent games. Definitely wouldn’t try to play games in 4k. I played through most of Rise of the Tomb Raider at either 720p or 1080p - that was probably the most recent mainstream game I’ve played through. If you can pick up an Xbox One S controller (with Bluetooth), a lot of games will recognize it and have decent config right away.
The GPU does not meet minimum specs for Rift or Vive. Barely misses for Windows Mixed Reality (they say 965m is minimum). This was the last generation of graphics cards where NVIDIA designated a different mobile vs. desktop line, so 960m in a laptop is not the same as a 960 in a desktop. For 1060 on, they will be the same.