LGA and Newark have zero customer service. Both Airports have hired the meanest, most rude people they could find and made them customer service reps.
Las Vegas ranked high does not make sense unless the rankings include number of slot machines at an Airport. LAS has terrible food choices, not enough seating, small restrooms, etc.
From there, I can usually get my car and be on my way out of town in 15 minutes or so. And the rates are very good compared to airports of similar size.
But you are right about the outbound flights. We usually eat where we gas up before the rental car return, somewhere close to downtown since The Strip is expensive and congested.
I used to fly through Newark and LaGuardia fairly often back in the 90s. Newark seemed to be pristine and LaGuardia was being remodeled. Wow, how times change. Being retired has some advantages since I no longer have to go to New York. :D