To add one more data point to the many here so far:
I installed this beta on my X as soon as it became available (to public beta users), so about 4 days ago. During this time, I’ve put the phone through its paces. Performance and battery life are very good, probably the best yet since I got the X in mid-November. No bugs or glitches to report. No random restarts. Works fine with CarPlay, calls work great, navigation, streaming music via Bluetooth, listening with wired headphones via Camera Connector Kit dongle and Dragonfly Red, playing games, streaming video, everything seems to be working as it should.
I’m sorry some of you are having problem with this beta. I hope the next one fixes them.