Everyone knows someone who has had luggage delayed, lost, or damaged. It's so common we don't need to go hunting for stories, they're all around us.
No, there are no reputable rental companies. You have to trust complete strangers that they followed every manual properly (both the rental company, and the people renting them), that they didn't have a minor crash and run so they don't have to pay, that every seat has been registered and any recalls have been fixed properly, that they keep on top of the expiration dates, plus then the poop/pee/puke/food that ends up in each one, and then how they clean it. Most people can barely keep up with their own seats, nevermind a room full of seats.
The CARES, while FAA approved, doesn't tighten the lap belt or have a crotch strap. The 44 pound limit means kids can only really fit in it for a few pounds, since the lap belt doesn't tighten until about 40 pounds. But they may hit the 40" limit before that point anyway. It's like suspenders on loose pants. The pants don't fall down, but they also don't fit.
Wendy