I have transferred through LAS several times but only stepped out once. So this review is from the perspective of a transit passenger.
There are slot machines in the terminal, literally a quarters throw from the gate! No matter what time of day it is you'll see people at the slot machines playing away. This is Vegas so that's okay. But a bit depressing when you see that at 7:30 in the morning. Same for the bars at the airport - people drinking that early (or that late).
Airport itself has a Greyhound bus stop feel to it. Cramped, sticky and soulless. Free wifi for 30 minutes, paid after that. Or you sign up for some spam.
Connections are relatively easy to make but not enough monitors for flight and gate information.
Overall a meh experience for a city built on image!