I think all inclusives are great because you really do get your moneys worth. It really depends on your all inclusive. Most usually have at least one bar like the lobby bar open all day. The pool bars are usually just open during pool hours. Some have restaurants that have dress codes (closed shoes, long pants, etc). Some require you to make reservations for dinner at the restaurants other ai's you can just go to the restaurant without a reservation. Some ai's limit how many times you can eat dinner at an a la carte restaurant during your stay.
For breakfast the ones i stayed at all had buffets. Lunch would be a buffet, some of the ai's also had a little beach grill to eat at too (burgers, hotdogs, that kind of thing). Dinner they usually have buffets and a la cart restaurants.
You can go on tripadvisor or expedia and look at each resort your interested in usually in the description it will tell you the hotel policies on dinner reservations, activities, what time bars are open, etc.