We've stayed CL at all the deluxe resorts, except for YC (we've stayed there, just not CL.) So the Poly lounge . . . our three boys (one in grade school, two are teens) LOVE the Poly CL lounge. It's their favorite of all the CLs for a number of reasons - super laid back, relaxed atmosphere, great view of the fireworks/castle, right next to the pool so completely convenient and friendly CMs who say "Aloha" but don't chat. They would rank the food better at WL and GF, but overall, Poly is their favorite.
My husband would rate Poly as his least favorite CL for some of the same reasons our kids love it - primarily the super laid back atmosphere and the fact that he has to see the castle and can never escape. He also thinks the food ranks low among CLs and that it's kind of busy with guests who utilize the lounge for dinner, order in their pizza or literally pick up a chair and place it directly in front of us so that we can't see out the windows. We actually burst out laughing when that happened, but we'd observed this family in the lounge before and knew that a simple "excuse me" would be futile.
So I'm in the middle. I love the relaxed atmosphere. The guy in the lounge last year who asked for yet another two beers for the pool and stumbled around singing "Do You Wanna Build a Snowman?" was seriously hilarious, friendly and didn't interfere with my enjoyment. I love the two levels and can always retreat to the upper level of the lounge and enjoy the view. We love to enjoy the fireworks from the lounge and then walk just steps to our room. For me, Poly is a combination of my family history there, the complete convenience of the entire resort, the outstanding theme, great dining options and overall happy feel. The new pool and Trader Sam's will make it even better. But the differences between the Poly lounge atmosphere and some others (BWI, GF RPC and BC, for example) have been significant in our experience.