I love AC Lounges. So much better than United's Red Carpet Club, and personally think it is much better than Lufthansa's.
My one downside...kids.
There needs to be a bit more of a crackdown on people who bring their kids and let them run wild. There should be a specific area for people who bring kids, and have it separate from the business travelers. I have seen United staff crack down on people before, and I applaud it. I am a very heavy traveler, and sometimes need the quiet space of the lounge to work in between flights. People changing their kids diapers, or having them loudly play in the same area as business travelers is poor service on AC's part.