Let's face it, to some of us it is about the food.
Everything else aside, which CL has the best food? This isn't about atmosphere, friendly CMs, size of the lounge, or any of that ...just food!
Out of my CL experiences which include: YC, CR (Atrium Club), BWI and WL, by far, WL has the most varied selection. There are usually 2-3 hot appetizers which change nightly and there are many cold appetizers, too. Here is a partial listing of some of the evening offerings:
Chicken skewers, ancho chili chicken skewers, salmon chowder, satay, venison meatballs, venison spring rolls, duck pot stickers, pulled-pork shooters, bacon-wrapped scallops, crab rangoon
They also always have a tasty variety of cold items such as arugula salad, potato and bean salad, buffalo salad, tomato caprese, antipasto platter, crudités, cheeses, hummus, baba ganoush, sun dried tomato pesto, bleu ranch dip, turkey and cheese roll-ups, PBJ shooters, breads
For breakfast they always have cut-up fresh fruit, including delicious fresh pineapple every morning. Apples and bananas are also out all the time. They also have fresh chocolate chip and blueberry muffins, croissants, pastries such as cinnamon buns, cereals, bagels (with cream cheese, jelly and peanut butter), yogurt, and oatmeal (only seasonally).
Every evening a delicious cobbler is available. Usually it's an apple, peach or berry cobbler. There are also Magic Bars, brownies and cookies and the portion sizes are generous. All the food is always replenished quickly, even right up to closing time.
I've never stayed RPC/SL, but from what I have read and seen, they offer a great variety of foods and have items other lounges don't, such as scones and cold meats at breakfast.