Not quite live but just returned from Prima yesterday and had Free at Sea Plus.
Staff was very quick to see and acknowledge the “Plus” and offer high end liquors, champagne, wine and waters. For example when I ordered an aperol spritzer at the Penrose, the bartender made it with Veuve Cliquot instead of Prosecco. (Not a waste of Veuve as I had plenty of her on her own as well!)
Most wine stewards were quick to know “Plus” included glasses and bottles. They all seemed to really want you to get the most for paying for the upgraded plan. Be aware, however, that different speciality dining restaurants on Prima have select wines and it can be difficult to get one you prefer when dining in another restaurant. They did try, but we had to compromise a couple of times. For example, Palomar has only organic wine and the choice is smaller than say Onda. The wine steward was very knowledgeable and led us to a wine we enjoyed. Waiters were quick to offer and refill waters included in the “Plus.”
Hiccups will occur, like a terrible gin used in a Negroni from the Prima Theatre Bar but it was right before show time and we should have specified the gin.
In general, however, we thoroughly enjoyed and used are Beverage Plus to full advantage on the Prima and the bartenders were awesome.