I'll start with the good. Baggage check-in and security were both smooth and easy. There is free WiFi, which made waiting four hours for my flight infinitely more bearable. This is the most aesthetically pleasing airport I have been to, as would be expected of an airport in a touristy city like Vegas. Some parts are quite detailed, and it is well decorated overall; the slot machines scattered across the airport give it a nice, "Vegas-ish" feel.
Here's the bad. The line at security can be long at times, and considering how heavily trafficked Vegas is, they could use more security staff. Also, there isn't a whole lot to eat, and the limited variety of food that is there is considerably more expensive than any airport I have visited. These few negative aspects only took away from my overall experience slightly, though; it is still the nicest experience I have had at any airport.