Yes, both resorts have heavenly beds. We have stayed in both. You really can't go wrong either way. The Dolphin is much bigger than the Swan, and it has a much more impressive lobby. The Swan is much easier to get around in because it is smaller. It took us less time though to get to Tubbi's and the grotto pool at the Dolphin from our room at the Swan than it did from our room at the Dolphin. Both rooms were on the East Wings, but the Dolphin is soooo much more spread out. We did have to do more outside walking than inside walking coming from the Swan, but that didn't bother us. It also seemed easier to get to the Boardwalk, then Epcot, from the Swan.
All that being said, I would stay at the Dolphin again in a heartbeat. I would just try really, really hard to get a room on the West Wing or even the Central Wing. I would probably just stay at whatever hotel had the lowest price and availability. Here are the major differences:
1. The Swan has two sinks and a bigger bathroom. One sink is in the bathroom and one is outside the bathroom. The Dolphin only has one sink, outside the bathroom, with a really big vanity area, plus a sit down vanity next to the closet.
2. The Swan has 2 queen beds and the Dolphin has 2 oversized double beds. I'm told these are one inch smaller than queens. We have a queen at home and didn't notice a difference at all, even with a small child sleeping with us.
3. The Swan rooms are technically a little smaller than the Dolphin rooms square footage wise, but because the layout is different I'm not sure if you really have less "living" space.
4. The Swan is a Westin and the Dolphin a Sheraton, but the service is excellent at both. The Dolphin has the Dolphin Fountain, laundry rooms, and two great new restaurants Fresh and Blue Zoon. Swan has Shula's Steakhouse, Palio and Gulliver's. Since the hotels are right across from one another, I don't think those should sway you much, unless you hate going outside and then inside again. Like I said, it was quicker to get to some of the places at the Dolphin from our room at the Swan than it was from our East Wing room at the Dolphin. Both hotels have rooms with balconies and are renovating the hallways right now, but I don't know what the timeline is on that.