We went to Blue Lagoon for the dolphin swim (not the encounter). Hubby went as observer, I swam. We did not do the beach as it was "cold" that day (only about low 70s). Wore wetsuits for the swim.
As far as the swim goes, it was definitely worth it!!!
I think he took about 100+ pics with our digital camera. When they had me pose for their photographer for the shots they have everyone do with the dolphins, he was on the dock getting shots as well. Observers can't be down on the platform, but the dock they do get on is right there, and they can walk around to get shots from different angles. WELL WORTH paying the $20 observer fee - which included his roundtrip ferry ticket. We still bought a couple of their pics, but hubby was able to capture a whole lot and they didn't seem to mind. The photographer even chitchatted with him.
Yes, it is worth it. It is a beautiful beach. We did not do the dolphins or stingrays- just wandered the beach, went snorkelling and lay in a hammock. There are hammocks everywhere. It was a beautiful relaxing day. We went in May
Only problem w/ Blue Lagoon, is that majority of cruise passengers choose this spot as it's not too expensive. Beautiful water, scenery and lots of hammocks and even some fish...but there were so many people in the water that I kept getting run over by the big water "trycicles" and bumped by other snorkelers. Gave up and layed in a hammock for awhile.