While I have no doubt that the Vizio has better image quality, you are clearly rolling the dice on firmware and product issues. I have seen people who are actually asked what others have run into because theirs works great, then they say that they have had to unplug it a few times on their own. WTH? I would NEVER buy a TV that has known severe firmware issues that requires me to unplug the TV. I haven't unplugged my dirt cheap TCL Roku TV since the day I plugged it in. Same for my Samsung TV that I've had for a few years now.
If you want phenomenal image quality that OLED delivers, I don't think I could stomach the headache that Vizio appears to have delivered. I would have to go with a LG C1 at the bare minimum, which means upping the budget... which may not be possible. Otherwise, I might stick with the U8G.
As is typical, if you are really stuck with a 55" maximum size, or appropriate size, then the Hisense is cheaper. You could go to 65" and maintain a $1,000 budget while the Vizio is $1,000 and only 55" diagonal.