In general I'm not impressed with the Comcast picture quality. I didn't have enough time to make an critical judgement for the XI5 and XI6. XI5 is not 4K. I have a USB stick that Sony gave out at CEDIA with some good 4K material. I usually let customers view the samples as a demonstration of what the TV is capable of.

I was back at that installation today and proved that one of the XI5 boxes is defective. The second XI5 box signed on to the wireless without a fuss. I did observe that the XI5 is not as responsive to commands from the remote.

These are voice remotes. One can ask for "4K" and be led to a few 4K feeds.