IMO there's many ways to think about this:
1. Keep up with the PBI. Your ability to stay up to date will be limited to if a PBI is released.
2. Use pkg, and then you'll be able to stay up to date based on who has provided the pkg files. This is more likely to be up to date than #1.
3. Compile your own versions from whatever source you want. This is obviously the "most" up to date because it assumes that the only reason you aren't the most up to date is laziness. ;)
I'll never do Plex on #1 because I like the bleeding edge stuff with regards to Plex. I also have a Plexpass account. I'm also fairly certain the PBI is not for the Plexpass version, and Plexpass versions are literally updated almost weekly.
I'm also somewhat expecting that #2 won't be the Plexpass version, so that's not a good choice if I want to use my paid-for version.
I've already got a working Plex server, so spending the time trying to do #3 is really not worth my time.
Now, if/when the PBI is surely on the latest versions, and is never more than 24-48 hours behind and easy to upgrade without an incident, then it *might* be worth my time to try it. Right now I have a server I can keep up to date very easily on my own, has never had a problem with upgrades(they take a whole 30 seconds.. literally), and has performed as well as I have needed it for. Until then, I'll stick with a separate Plex server. ;)