x264 / 4k ~ 30Gb Most of them can play (Pc, tablet, phone, TV)
x265 / 4k ~ 20Gb Some devices are play. (Pc, TV)
At first I collected movies to watch. Most of me download 4k (choose high capacity to watch), but when the hard drive is full, I can not watch it on the phone because it will load. Later on, I only choose to download 1080 x264 ~ 2-3Gb/file. Don't choose 1080 x265 ~ 1.5-2Gb/files if your device doesn't support it.
Optional DD + or DTS sound if you have a quality speaker system, if not, choose ACC.
Stay away from REMUX (> 40Gb) versions if you don't need multi captions and subtitles.