h.265 gets blurry, h.264 gets blocky. Higher quality encodes, especially of film will degrade worse in 265. Hardware is also much worse in terms of overall support for h.265.
My Nvidia Shield TV is the only small/arm device I've used that can reliably playback 4K h.265 video, specifically network content from my NAS (Kodi).
h.265 is much more common as an option for TV feeds, the quality is usually lower than BR anyway and the smaller size leads to better near term gratification, you can get a 1080p h.265 for often smaller than the 720p h.264 which looks significantly better.
I tend to prefer it for my own rips as I get a much smaller file size, which is starting to get scarce on my NAS. I prefer the blur to the blockiness myself, and my vision isn't the greatest anyway. YMMV.