I'm looking forward to it also. I don't have any other content than samples and youtube stuff but as you've probably seen most youtube 4K is very compressed.I've got a few samples, looking forward to 4k BluRay for a good source of 4k content.
I've tried a good variety of games so far and most tolerate the 4096x2160 pretty well. A few that don't get black bars put on the sides when running at 3840x2160. The performance hasn't been bad either.