In early March, we will be staying at the Dolphin for our sixth time. We love it. The beds really are heavenly. The rooms are very light and airy. The staff are helpful and nice. And the location can't be beat!
We always stay using the gov't rate. My best advice, if you haven't done it already, is to sign up for the Starwood Preferred Guest program. Our very first stay, when I had absolutely no points accumulated, we were upgraded to a balcony, Epcot view room. No need to be coy like at a Disney resort, you're just upgraded if something is available. Now, I believe you're going at Easter so there may not be a room available but there is a possibility. We were there the week before Easter last year and were upgraded to a balcony room with a view of the Tower of Terror.
We've always used Tiffany Town Car and been very pleased with the service. They're waiting right there for you as you come down to baggage claim and you can request a grocery stop. Frankly, I'd rather take some of the money I've saved on my room rate at a deluxe hotel and use that for a town car service and not have to wait around for Magical Express and then a long wait for my luggage.
The only way you'll know is if you give it a try. We stayed at the WL for a few days on our last trip and, even though we thought it was a beautiful resort, we were happy to get back to the Dolphin. The rooms at the WL were dark, we hated the transportation and not being able to walk to a park, and the counter service restaurant did not have as many varied choices as Picabu's. Everybody likes different things--you may be pleasantly surprised.
I've recommended the Dolphin to many of my friends and they've all really enjoyed the resort.