This is one of the worst airports in the US.
First, if it all possible only take carry on luggage when flying into LAS. It often takes 30 or more minutes for your bags to start arriving on the belt. This is a huge pain for me, as I generally prefer to check everything.
Short term parking is metered. I do not carry change, so I have to plan for this when picking others up.
Now I am sure you are asking why would you have to park to pick someone up. That is because it can be nearly impossible to drop off or pick up people curb side. Traffic clogs up easily and often.
There is no Sky Club or partner equivalent. This is actually more of a Delta issue, but I can not blame them for not wanting to invest much in this airport.
The taxi line can be rediculously long at times. Apparently flights come only in bunches to LAS. On that note for those of you without a lot of experience using taxis, be careful, Las Vegas cabbies love to rip you off with the scenic route that they claim will take the same amount of time because it avoids traffic. I have had several friends that do not travel much get ripped off by this tactic.
Security here is rediculous. The line is often gigantic. Planning is clearly optional for the TSA here.
My last complaint is one of the biggest for me. The only major airline that considers this airport a hub is Southwest. I know Southwest refuses to label hubs, but lets be honest with ourselves. LAS is a Southwest hub.
The one upside is that the airport is very close to the south end of the strip.