We’ve stayed at both resorts numerous times and actually done both on a split stay before so comparing them directly is fairly easy for me. Note that I’m a huge Poly person, just got back from another stay, with a solo trip in like 2 weeks. Meanwhile I really only enjoy BC/YC stays of 3-4 nights because any longer than that and the many things about it I don’t care tend to start overshadowing what I like about it. I’m also a weirdo who doesn’t like SAB though lol so keep that in mind.
They are two very different resorts, in theming, amenities, and general vibes. I vastly prefer the Poly on pretty much every metric. I don’t care for the recently redone YC rooms and much prefer Poly rooms, they’re huge (enough that 3 adult women didn’t feel cramped at all on our recent stay) and I love the Moana theming, it’s very nicely done. We are balcony people and didn’t get one this last trip but tbh we really didn’t miss it! It was fun seeing the monorail from our window.
Re: alleged “chaotic” nature of Poly. Always, always utterly baffled by these complaints. The main pool, sure, but the quiet pool’s better anyway, and it’s not like SAB doesn’t have its own issues with crowding. Unless you like to hang out in resort lobbies all night this is a total non issue to me. We never have issues getting food, shopping, etc. And during the day it’s just as empty as any other resort because most people are at the parks. A lot of people don’t like that it’s not all in one building like YC, because it can be inconvenient when it rains, but the Poly grounds are so beautiful to walk vs boring hallways on hallways.
Everything that makes this resort so popular to visit is even better as an actual guest. Can just put your name on the list for Trader Sam’s while at the pool and don’t have to wait around. The dining is so good there, esp the quick service options, and having that on site without needing to rideshare or schlep on buses is huge to me. Wailulu in particular is insanely good, probably one of the best resort restaurants right now. Sure Poly is lacking a signature, but does it matter when you’ve got Citricos and Narcoosee’s a short walk away? Which is the other benefit btw, being on the monorail is so convenient. Some of the best lounges just a quick hop away. Monorail crawls are legitimately so fun and even better when you’re staying at one of the resorts. You can decide to just do it on a whim, like we did a couple Saturday nights ago.
If you love the fireworks views at YC, nothing beats watching HEA and then walking like 2 seconds back to your room. Even if you don’t have a theme park view room, the beach is still way better than camping out in the hub. No waiting out crowds or dealing with actual chaos, trying to leave MK. You can also watch the EWP, which is so cute and kitschy and fun.
I agree with the advice to maybe do these on a split stay. Maybe end at YC since you know you love it already. But I love Crescent Lake/monorail splits, it’s my absolute favorite way to do WDW. Best of both worlds. The transportation advantage is huge, only needing the bus to AK. If you like the Friendship boats the way I do, you’ll also enjoy the resort launch between Poly/GF/MK.
Re:CL I agree it’s probably not worth it. We’ve done a night of it post cruise at Poly when we planned on not going into parks, and imo scenarios like that are the only way I’d do it again. We enjoyed it a lot but it’s not worth the premium to me otherwise.