I've done both the Encounter and the Swim, and enjoyed both. I booked them on my own, so I was on my schedule, and it was cheaper. It's easy to get a taxi to the boat to Blue Lagoon. You have a 30-40 ride there, the talk, and then the dolphins. In the Encounter, you stand in water up to your waist & the dolphins interact & dance with you & of course, you kiss them! The only negative in the Encounter that day was a mom who was overbearing & demanding....but we ignored her.
In the Swim, you actually get into the water with the dolphins & do the interactions, with the grand finale of two dolphins pushing you thru the water--wonderful! Of course, it's more expensive.
I really enjoyed both. It was easy to book on our own, and yes , it does take some time to get there & back, but I also enjoyed the boat ride. The video I have of my daughter & I doing the swim is priceless!