I just returned from the Miracle on the 10th. We did the Blue Lagoon excursion. You have to take a bit of a walk to the calypso boat, which then takes you on a 45 minute ride to the Blue Lagoon. It's a secluded, beautiful beach where you stay for the majority of the day. You get one complimentary rum drink when you get on the beach, although the line was so long we didn't wait for it. There is a bar where you can purchase drinks (Beer is $5 Soda is $2 Mixed drinks $5 or $6), very expensive food, tubes and kayaks to rent..... it was a great day, very relaxing. Just fill up on a large breakfast/lunch before you leave the ship!! Yellow Bird Party Boat is a triple deck catamaran. There is a Calypso band and complimentary rum or fruit punch as you sail. Nothing free once you get to the private island. Unless you are enticed by the free drinks on the boat, I would recommend Blue Lagoon. They are both $29 per person. Whatever you decide..have fun!!!!
The Blue Lagoon excursion alone is $29 per person..adult or child. Blue Lagoon with sting rays is $49 per person. The sting rays are in approx. 10 feet of water (so I heard), so you have to float on top of the water. It's not like you can stand on a sand bar and enjoy them up close. This is all second hand, we didn't actually do the sting ray excursion. I have a 3 year old who enjoyed swimming in the crystal clear water all day. That's all she needed to be entertained! Whatever you decide..enjoy!!!!
I've done both (just returned from Glory 7/10 cruise). Just did the Blue Lagoon and it was better than Yellowbird as far as the beach and snorkeling. there were hammocks everywhere and picnic tables. But if you want to party you might do the Yellowbird.