Hi we booked premium seats for both legs of our journey in May and the outbound flight was great... also it was super to have out own dedicated check in.
Some people were offered upgrades at the welcome meeting in resort.for the return journey at a very good price. Comparing the two levels of service I would say that coming back the crew were very tired and we did not get a really top class service particularly compared with the outbound, and the dedicated check in at Samana was just going to the front of the queue.
if I was doing this trip again I would book extra leg room and upgrade my inflight entertainment both legs of the journey - if you need to sleep then premium is a little quieter but you can still be next to a screaming child whichever section of the aircraft you are travelling in.