It’s FAR from a no brainer. It all depends on what type of coffee you drink, what size coffee you drink, what ship you are on and who the F&B manager is and how they interpret the punch system.
It isn’t always a good deal, and in some instances can be a money loss
Sandals is ridiculously expensive. Like you, I am very hard pressed to find an AI for a week that is anywhere close to what I pay for a week long cruise.
Yes, even at Sandals. We went to Sandals in St Lucia (visited all 3 properties), the liquor was LOW grade and definitely light on the pours or watered down