When I initially install iOS 11 beta OTA, there was a little lag. I’ve yet to experience any crashes, with the exception of the Trello app, but that doesn’t really count because an app update will fix it. The rest of my 3rd-party apps work flawlessly. Anyway, after I took some time to install a fresh copy of iOS 11 and set it up as a new device, I don’t even have any more lag or I should say rare lag. For a beta 1, iOS 11 is stable enough for a daily driver. In fact, I’m using it as a daily driver. Wi-Fi, Bluetooth, Pay, VPN, etcetera, all work. I’ve not experienced any dropped calls or wireless disconnections.