As long as we're talking US airlines providing good service, I had a great experience at Delta's lounge in SFO a few years ago. I was booked on DL to LAX and onward to SYD on VA. My SFO-LAX flight was cancelled and there were no others that would make the connection at LAX. The VA/DL partnership at the time wasn't well known outside of LAX, yet the DL lounge agent knew the basics and knew exactly how to confirm more details when needed. Importantly he believed that the VA ticket stock could be endorsed to Qantas (which had space on a nonstop SFO-SYD that evening), even though this wasn't available to DL-issued tickets. He quickly phoned the VA station at LAX to confirm this, got my tickets sorted, and arranged for my checked baggage to be returned so I could re-check it at the Qantas desk and have it tagged properly. Bonus, I was able to double-dip and get both ORC credit on VA plus Qantas points for the flown SFO-SYD. But more importantly this agent's knowledge of ticketing rules for an airline that didn't even fly to his port, meant I got home on time. So kudos to US airlines for empowering and training their lounge staff and senior ticket agents to this level.