I would go for the balcony cabin every time, but that's my personal preference. I would much prefer to see the sunrise/sunset from my balcony, watch the scenery go by, hear the water rushing by at night, than spend about an hour getting a massage. The massage gives me a temporary good feeling - the balcony makes me feel good all week.
Serenade of the Seas b2b January 2016
Serenade of the Seas b2b January 2017