This might be a little controversial, but after my visits today:
Qantas > Cathay = BA > AA
Too many people know about the Cathay lounge now. Despite there being no actual Cathay flights at the time I visited, it was pretty busy. In fact, the first class area was busier than the business class area. Also, for some reason they were unable to serve hot food this morning. But I do like Cathay Delight
At least BA had hot food (albeit not the healthiest!) No more LPGS but I like Taittinger. And quieter than the Cathay Lounge.
AA is pretty underwhelming, apart from the sweets.
Qantas a clear winner. The staff were really welcoming and explained the food and service. Having two levels makes it feel more spacious. The food looked a lot healthier and appetising. Excellent gin bar. And much quieter than the others.