McCarran is not my favorite airport to fly in and out of but it could be worse.
What are the detractors? Let's start with the security line. Even thought there are three terminals the design of the airport creates long security lines. I have had to weave back and forth though the que many times. You definitely need to leave enough time to get through security here.
Second is the taxi que. While I am impressed with the efficiency of the loading process the taxi line is another exercise in turn style madness. The line can be very long winding you back and forth through the madness while luging your bags. This last time i did an Uber instead, but they have made it very hard to find the pickup location to deter people from avoiding the taxi line. Still doing uber the next time I go, it is so much better.
On the plus side:
The videos at the security check points are great. TSA or the airport actually took advantage of the creativity and talent of Las Vegas and made some great videos about going through the security, which you have plenty of time to watch and you wait in line.
There are numerous food options and shopping available in the concourse. While you will pay airport prices, at least you can get a decent bite to eat while you are waiting on your flight.