Personally I don't have any problem with Hertz, Enterprise, or Avis in cars or service quality, the one I have problem with are usually the lower tier brands that aren't the flagship / business travelers, they always try to pull a "we don't have your car so you must downgrade, or pay to upgrade" on me.
I've shopped Hertz's used car lot and they are pretty good condition for a reasonable price (no haggle). I'm sure if you overlook the best condition you can find a better deal on your own, but that's not how they sell their cars so I think they are fair. The way I see their bankruptcy is the public ownership in stock market is always pushing for high debt, stock buyback, high dividend, and risky bets (lease a lot of vehicles and get stuck with them in a downturn). This bankruptcy is to get out of these lease obligation and let the manufacturers take back the vehicles, layoff employees, get out of non profitable locations' lease, etc. The owners took a hit but the management get out of jail free.
Screw Wall Street and leverage buy out, they always ruin perfectly fine companies with their greed. I think private ownerships and family businesses have their places at least in the long term sustainability. The manufacturers may delay production start or reduce shifts due to social distancing anyways, so the market may digest some of these used car return or future fleet deliveries cancellations.