So as the title says, tails has been upgrading to 1.8 for the past 3 hours, nearing 4. It has already downloaded, that is not the issue. Its on the "Yours Tails device us being upgraded..." screen and has been all this time. I do have a persistent volume I am worried about, though if it is lost the only true bummer is my password list being wiped and javing to start over again, which in the end is probably a good thing for OPSEC.
So should I cancel the installer and try again or wait it out?
Wait it out. No need to risk corrupting the drive.