We stayed on the beach on our first 7 trips and last year and this year split our stay like you are planning (about a week on the beach and 2-3 days at BCC).

Nothing against the cliffs except we get really bored during the day and we both agreed that going forward we'll stick to staying on the beach, we just enjoy the goings on that are the beach. The good thing about Negril is it's real easy to get to the beach from the cliffs.