Welcome, Janet.
If the search function was working you would be able to find loads on this topic!
However,
The Dolphin is considerably larger (which makes the Swan my hotel of choice). I find the Swan 'cozier' - if you can call any hotels that size 'cozy'!!! I just find the Dolphin more intimidating.
The Dolphin has Tubbi's for 24 hour food availability & also the laundry facilities if you need them. We, however, could arrive at either of these in 5 minutes from our room on 12th floor @ Swan - we could probably make it quicker than some of the people at the other end of the Dolphin!
The pool is off to the side between the two pretty much - probably closer to Dolphin. The lap pool is closer to the Swan.
Kids seem to like the Dolphin better because of the atmosphere in the lobby etc. But my DD loved the Swan.
If you have a rental car, I believe parking at Swan is probably closer to the building. We went down the elevator on the convention end and walked out past the convention rooms and were at our vehicle in minutes - we never used valet parking.
Both are equal distance to the Friendship Boat launch. Just a few steps further from Dolphin to the Boardwalk - Swan is slightly closer to that.
We picked the Swan for bed size mostly also! My DS is a little over 6 feet so I felt he would be more comfy there.
Really - you can't go wrong with either facility! Some of the Swan rooms are already renovated if you wanted to take a chance and ask for a renovated room you might get to experience one!