I went to high school there in tenth grade(1990). Its not a bad school but its not poway high (where I went to eleventh and twelfth grades) ethier. I never saw a rat, and traffic only seemed bad to me when I was actually in the military and driving on/off at rush hour.
I would live in Coronado again, but mind you its not as safe and village like as you might imagine. There are the wealthy and the military and not much in between. So you have the toxic mix of those two classes. Its kind of Palm Springs like in that regard. It is however, a very pleasant place.
As for the Cays the real reason to live there was having a dock. If you don’t have a boat, I could never see living that far from a grocery store.