I love Swolphin. You absolutely cannot beat the price for the location. They can frequently be had for under the price of a moderate even counting the resort fees, and have the same perks as the deluxes in the area that cost hundreds more per night. I genuinely prefer the food and amenities there too, even when staying at the Disney deluxes nearby we always end up eating at Swolphin at least once. We did dinner at Rosa Mexicano on our May trip during the BWI part of our stay. And I actually prefer the pool complex to SAB, I feel like it’s way less chaotic, no chair hogs, and you can order food with a QR code on your chair.
Only downside is the loss of the Disney buses which means dealing with TTC but with the money you save you can just take Minnie Vans to MK if you don’t want to walk to YC or BWI for buses.
I think the theming argument is kinda tired if I’m honest. The Michael Graves architecture is very polarizing but I think it’s whimsical and makes these hotels feel less like regular Marriotts, like they belong at Disney (the Swan Reserve does look and feel like a boring office building though). You’re sitting right on Crescent Lake looking at the Boardwalk. And frankly BWI is the only of the Disney deluxe trio over there that feels interestingly themed to me. But I grew up staying at the Dolphin on family trips when it was first built, so I have a lot of childhood nostalgia for it.
Unless you stay there during a convention it’s all park going adults and families. I usually do a Labor Day trip every year there and never see conventioneers. I tacked on a couple of nights at CR ahead of my Swan stay this year just for ease of access to MK for the Halloween party though.