I stayed at the Swan for the first time last summer and you can see I'm going back. We loved it!!!! I haven't stayed at the Dolphin but it's definitely louder and people on conventions tend to stay there more because of all the restaurants and the health club being right there. The Swan had a more intimate feel and was alot cozier for our family.
I have 2 teenage boys so I needed the 2 queen beds where the Dolphin only has double beds. I also loved their bathroom area. You get two sinks, one in the actual bathroom and then a sink right in front of the closet.
Our family are Epcot fans so it was great being able to just walk to Epcot if we didn't want to take the boat and the Boardwalk is right there also. The pool is huge!!!!! They have a lap pool and a quiet pool which is closer to the Dolphin and then a large quiet pool by the Swan and then the main pool sits in the middle of both hotels. They also have a separate jacuzzi/hot tub area near the main pool.
The staff is wonderful and if your staying club level as we did they will handle all your PS's for you and the lounge area is always staffed and they have plenty of food. Thabo is the greatest!!!!!
My only wish is that the Swan will get their own laundry room. I don't know why they don't have their own but you have to walk to the Dolphin to use the laundry room which wasn't so bad since I did it every 3 or 4 days. Carrying the folded clothes back was tough but I would just call my DH or my boys and they'd come over and help me. Women....we just can't ever get out of doing laundry..even on vacation. But for me, I'd rather do it there and come home with clean clothes then have to come home and do it. I also like to travel light so I pack half the amount and then wash and rewear it. We spend almost 2 weeks there so for me it works alot better.