Yup...same here. Lucky us. I've had nothing but problems throughout the entire High Sierra beta program. It was so bad, with gray screens on a 2015 iMac, that I switched to the Public Beta profile. It improved somewhat. Usually, no amount of gray screen troubleshooting (unhooking peripherals, PRAM resets, etc.) would prevent me from having to Time Machine it back to where it was. I ran the full install and it took me back to 10.13. The 10.13.1 release finally showed up in the App Store - gray screen. This time I was able to successfully troubleshoot and got it up and running but man what a pain the tookus. Now I'm reading that 10.13.2 is the beta to have that will solve issues 10.13.1 didn't solve.