I stopped doing OTA updates for iOS many moons ago. I always download the firmware and alt+click "check for update" in iTunes and pick the firmware file. Apart from battery issues in beta 1 I've not experienced any of the issues.
Add me to that club as well. I've heard way too many bad stories about OTA updates.
That's my method, as well. It's worked well in the past for me and I'm doing the same with beta 2 right now.
FWIW, I adopted a modified version of this a couple of years ago - although I completely agree with your MO here.
In the case of my iPad 3, with the clean B1 and OTA B2, if the first beta seems pretty solid I'll keep it, then test the OTA. If the OTA seems pretty solid too, then I'll use that for 2-3 days while I test out my apps. Then, after those 2-3 days, I'll perform a clean install of the newer beta with no restoring from a back up. If the newer beta seems to bork anything right away, I'll first attempt a "reset all settings" and/or perform a clean install sooner - either way I test a clean install regardless of the OTA.
I also performed a clean install of B2 on my test iPhone 6 - performance is much improved, with a couple of caveats. I noted that some of my account information was present in the "clean install" - I have different iCloud accounts for my workflow (main account) and App accounts (iTS/App), and saw that the clean install did not wipe the user account names from the relevant fields. Next, my iPhone 6 had some issues waking up after some light use - Siri wouldn't start, pressing the Home or Power buttons lit the screen but wouldn't provide me with a usable screen, and TouchID wouldn't work; I powered down the device and the Power button wouldn't turn on the device - only inserting the Lightning cable woke the device. I'll be submitting a bug report for this - FYI; the device was fully charged, had been used for data and calls, and was not warm to the touch.