Pretty efficient, even though I got a little lost between the terminals and had to go find the shuttles between the two.
However, the new wing is clean and not indicative of the older wing of the airport which is older, dingy, and reeks of the high hopes and dashed dreams of thousands of tourists that flood through this airport. TSA interactions have been smooth and with no incident. Waiting in line isn't an issue since I time these and plan ahead, instead of other idiots that rush in an hour before and expect to be cleared. That is on them, not TSA.
I like their coffee selection and the exit out to the baggage claim is easy to follow as well. Security is also on top of things since I ran into a bunch of them riding bicycles outside.
Overall, my flights in/out of McCarran have been without a glitch.