Pros and cons to both of them. Both packages will include the WIFI and Gratuities, up to 15 alcohol drinks per day, unlimited specialty coffees and teas, soft drinks, bottles of water, etc. If you enjoy the specialty dining and do several per cruise you will get one free on the first night as a suite perk, and two free with the package. If you like to dine at the casual dining venues, you will get two with the Plus and unlimited with Premier. Wines by the glass up to $15 with Plus and $20 with Premier. With Plus if you order a glass of wine over the $15 you will just pay the difference +18% service charge. ($17 glass will cost you $2 plus 18%) You get the same 25% discount on bottles of wine with both packages.
Premier package is $20/pp/day more than the Plus but you get other freebies not included in the Plus package. You will just have to weigh the benefits and choose. If it were I, and I was getting a free cruise, I might spring for the Premier Package.