In my never-ending search for the BFH (Burger From Heaven), I had one at P.J. Clarke's.
It was quite good, but not sublime. Certainly not in the same league as Burger Bar or Bradley Ogden.
Most notable single element was mozzerella as a cheese choice; I wish more restaurants offered that.
The service at PJC, however, was some of the best I"ve ever had at a Vegas restaurant. From the host, to the wait staff and busboys, it was : prompt, friendly and efficient. You know how some times you leave a tip because you think you have to...In this case, I wanted to.
And by the way, there is a back-room dining area that is quieter than the more touristy front area, and has a juke-box (free) with some of the best music ever: from Sinatra to Ray Charles to Nat Cole to Stevie Ray Vaughn. That makes everything better.