Wow, that's a super price! But I'd spend the extra $17 to get a second matching RAM chip -- not only will it run better with 8 GB, it always goes better with two matched sticks of RAM.
With a 4K display you can get resolutions like 2560x1440 but only at "low-resolution" -- that is, not in Retina mode, only in straight 2560x1440 mode. I believe that's an issue with the video drivers, because I think the Broadwell NUC can do Retina modes over 1080p, but the Skylake NUC cannot. It may be that you could get it working by tweaking the video settings in BIOS, but it may just have to wait for future OS updates.
And there's a long list of components in the first post that don't work -- WiFi, SD card slot, IR, and NFC come to mind. Some people who are dual booting have gotten Bluetooth working, but others have reported that it drains the batteries of their Bluetooth devices.