The way I see it... It all depends on what your looking for...

AI PROS- Included activities, included food (buffet or Ala carte) and drink, included alcohol (diluted)(usually not top shelf), and they are usually pretty fancy if you like that.

EP PROS- choose location on beach, choose what you would like to eat/drink, can get your top shelf drinks, culture is at easier access, don't feel obligated to stay at hotel...

SOO... depending on how fussy of a traveler you are you could do either for the same price. i found EP to be cheaper for us we don't need all the fancy. we are paying this trip about 4000 total for 14 days, last trip was AI was 3000 for only 4 days 5 nights at a RIU... both prices are air fare and everything factored in food/drink etc. granted I don't really drink alcohol... my other will be on his Red Stripe kick I'm sure.