I have the Synology 923+. I went down a research rabbit hole that spanned far too long. First the DIY route, then the prebuilt. Then I dove really deep into the arguments with the 923+ about it having AMD instead of Intel, so it being bad for plex transcoding. All in all, I love it and have been super happy with it. I watch plex off of it just fine, but all of my devices are new. Some of the synology stuff has been a bit wonky with Docker, but otherwise it is working great and I’m very happy with my purchase. I havent needed to upgrade the RAM yet or get a cache drive, but I like that I can do upgrades in the future as I stuff more processes on there, as well as upgrade the drives (currently have 2) as I need more space.

Have a link to that hacker news discussion by any chance? Would love to read through that.