I actually really like McCarran, maybe because I'm used to the suck that is Philly.
McCarran is clean and easy to navigate. The security lines move along and are generally efficient. There are flights to and from just about every where. The best part is you can booze and gamble while waiting for your flight.
The worst part about McCarran is the taxi line trying to leave ... it's awful and takes forever. There's a rumor they're going to expand the monorail to the airport, but that makes way too much sense for a government agency to follow through on it.