I don't have any evidence to backup my statement, but for my usecase (Linux booting troubleshooting toolkit) Kingston sticks last a fair while (~10 years), but Sandisk fail sooner (<5years?)
The main thing I've noticed for all brands: there's no warning before failure. They're like nicad batteries... all good, then one day - completely dead. So never keep any data on them that you can't lose.
I have rooftop solar, but only for the house because I can't reach my car to charge it in the street.
The car sits outside for days (I work from home), so in my case this would be great.
This is the 1st I've seen of this car, so haven't read any other details, but I'd be surprised if external charging wasn't possible.