Just another Plex owner/user who would like HEVC transcoding. I have 35mb/s upload speeds and my brother still encounters intermittent buffering. He is not overly savvy and just compares his experience to what he obtains with Netflix. Netflix almost never buffers and plex consistently does. I know it’s his bandwidth and setup at his house as I have a number of other users (friends) with better bandwidth and they experience no problems. HEVC, I believe, would help alleviate this issue by better utilizing the limited bandwidth available.
Oh, and for those that suggest just transcoding everything before hand, I will not do that for two reasons. My plex server IS my backup of my LD, DVD, HD-DVD, and Bluray collections. I have over 9K movies collected over 20+ years. I’m here to tell you, even stored in an air conditioned environment, discs can and will go bad. So going back to the original media can be impossible. That being said, transcoding from a previous transcode will loose quality over time. Therefore I will store the data as originally ripped from the discs and then use the best codec I can in a live transcode to deliver what I need. At this time, x265 seems like the best codec to do that for max compatibility and the best bandwidth utilization. As is always the case, compute power becomes easier and easier to come by and implementing x265 live transcoding, though possibly a challenge now will be nothing in the next couple of years. If the plex developers continue to wait, this whole conversation may start again with the AV1 codec and maybe they should move in that direction now with the idea that hardware support will become available over the next year of two. The intel ARC cards may end up being our saving grace with QSV/AV1 support at an acceptable cost. Maybe we could start with an Intel cpu and upon hitting the upper limit just pop in an ARC card… change none of the configuration… and increase our number of streams and quality that easy. I know… Pie in the Sky dreams. 
