There is a new priority pass lounge in (McCarren) las, it is located in the d gate area, a little tricky to find--it's in a corner and marked "club las" (to the right of the down escalators).
It is very small, 24 seats in the main area and another 8 in the computer section (plus 6 computer seats)--but there is only one computer terminal plus monitor--the other 5 seats are for those with their own laptops.
There is a bar and they have a few packaged snacks and coffee, juice etc.
But it is much better to relax here than at the gate.
When I arrived around 9 am there were about 16 people in the lounge, by 10:15 am, I was the only one.
[PS: Priority Pass Select pax can no longer use the United lounge.]