I don't know how much help I can be, but I have stayed at the the IB*Tucan (8/05) and at the Barcelo Caribe (2/06) I enjoyed the IB* more. I thought the food was better at the IB*, I liked that it was fairly close to Playa (only a 5 min cab ride), I liked the fact that it had the Palapa's on the beach, where as the Barcelo didn't, but you can rent an umbrella I am pretty sure. I just thought that I Barcelo was too big. Not saying it was bad, just bigger than I wanted.
They both seemed to have lots of things for kids to do and all the children we saw seemed to be having a fantastic time. Believe me we were watching out because we're planning on bringing our toddler with us next year.