The itinerary that you are sailing may come into play, as a lot of people find it more beneficial to have the different drink packages if they have more sea days than port days. Last fall, I did an Eastern Med cruise that was very port intensive and spent time considering whether any of the drink packages would be worth it to me. I ultimately purchased the premium alcohol drink package and after taking the cruise, still think it was a great decision.
My habits may not be reflective of yours or others on these boards, but I like to start my day with a cup or two of espresso and also to have one after dinner. Add to that a bottle of water or vitamin water to take off the ship with me in port, a martini or two before dinner and two glasses of wine with dinner, and then another bottle of water to take back to the room with me. Even on the port days it came close to "breaking even" or did break even. On the sea days, it was nice having a few drinks with lunch and while relaxing by the pool.
It was also nice not having to sign slips, and the service remained top notch.
Again, for me it was worth it but it may be different for you.