I have stayed in all 4 hotels.
POFQ - It is a lot smaller that the POR so no matter where your rooms are its never a long walk to the pool or the food court. The bus stops there first so its easier to get a seat on the way to the parks, its nice to be dropped of first especially if its busy and you have to stand.
POR - Scenery is beautiful, there are two types of rooms - mansion rooms which are more of a elegant, romantic style and aligator bayou which are more rustic. We stayed in Aligator bayou in building 24 which is a trek from the food court but right near a bus stop and a quiet pool - most of the time we were the only ones in it!! There was a lot more wildlife around POR, lots of ducks, rabbits etc. We are going back here in April.
Dolphin - We have been here lots of times. The location is great - walking distance to MGM and Epcot, the boardwalk is great at night. The beds are great!! Softest beds ive slept in! The rooms are quite large. However my last 2 stays were not great.They tend to have lots of conferences and on numerous times in our last stay they closed off the pools and/or lobby for the conventions. After 10 visits i personally feel their attention is now more focused on business people and not people on holiday! I wont be returning.
Swan - basically the same as the dolphin but a lot smaller, only have the one lap pool but you can walk over to the dolphin for the grotto pool - the cheaper eating places are all in the dolphin so i wouldnt stay here again.
My favourite out of the 4 would be POR - its hard to beat disney service and the resort is really beautiful!