I've stayed at the Courtyard. It is a nice enough hotel, only 100 yards from the beach. However, they were very disorganized. If you chose them, whatever is part of the deal, have them give you a written confirmation. They are going way up in price!!!! In 6-03, we paid $89, which included the shuttle. Now it is around $150 and up!!! That is what I was quoted for 6-06.
I have not stayed at the Doubletree, but I did seriously look into this for 6-06. I was quoted $120. The room layouts look pretty cool. They are not much farther from the beach, a few hundred yars.
Personally, given the choice, I would go with Doubletree.
I am however going with Comfort Inn at $99 because of the price. It is located basically next to Courtyard.
I may even go to Motel 6 at around $70. A room is a room is a room as long as it is clean. There have been many good comments about this hotel from these boards.