When I was in AC, Belize this past November my group stayed at Ramon's Village and we also did our diving with them also.
If you are diving I recommend that you ask for Palmer and Nino. They are both young guys and did an excellent job as dive masters. If you do decide to dive with these guys tell them Brett said hi.
As far as restuarants to eat at, Elvis Kitchen is great for dinner. Celis is a really good place for lunch. I recommend that if you are looking for a cheap meal to get away from the resorts. Look for a little run down place and they are usually the best. Don't look for the typical menu either, the best ones only have a few things to choose from but they change from day to day.
Feel free to e-mail me at firstname.lastname@example.org for more info.