I currently have two cable boxes in my home: A MX011ANM XG1 which is on the main TV we watch all the time and a PX022ANM XG2v2P that is on another TV that is not watched that often. Is it a good idea to swap out the boxes every once in awhile? Are the newer ones faster? I do notice the XG1 box I have does seem to have some lag when navigating the menus and stuff. The other one does too but I don't know if that is just normal lag plus I don't use that one that much. I know there is not a lot of 4K content on Xfinity yet but is it still worth it to get a 4K box? Which boxes are currently the best? Let me know what you think I should do with these two boxes.
The xg1v4 is a nice DVR and has some internet streaming apps. If you watch Netflix/Amazon Video/YouTube and don't have another 4k player for them, it might be worth the trouble to swap. There are also some on-demand movies you can get in 4k. The voice feature on the remote control is also nice, although personally I like the X11 better than the X15 that comes with it. If you pick it up at a store they might let you trade.
The 4k list of on-demand movies shows about 60 in the list (which I didn't expand). There are a few free ones like documentaries on Australia and turtles that do have impressive detail. And there are some sports events listed here: https://www.xfinity.com/support/articles/uhd-4k-faqs. Thursday night NFL football may or may not get added depending on Fox being able to send the right format.
The quality of normal TV content should not change enough to tell a difference. It will just be the x1 box doing the upscaling instead of the TV. I'd definitely upgrade if your current box doesn't have the voice remote (X11 or X15) because that's a nice feature. And I wouldn't say anything is worse about the xg1v4 exept maybe losing the clock which was too dim to see on my previous box anyway.