All-inclusive, family-style resorts like Beaches, Sandals, Club Med, Iberostar & the like are not by design, intent or in fact dedicated dive resorts. Scuba is a sideline for them, just another water activity for its guests that want it. A few are more dive-focused than others, e.g., Club Med Columbus Isle/San Salvador/Bahamas, but still it is never their primary focus. While there may be an exception to this out there some place, Ive yet to hear of it and the above is the general expectation
At any Beaches or similar property you will dive their regimented schedule with a widely mixed bag of divers, meaning that you won't dive the more distant or more challenging sites on any kind of a regular basis, if at all. Youll spend most of your time diving Grace Bay. You well may have resort coursers, snorkels & even bubble watchers on the same boat, and you can be guaranteed that the boats will not be small, fast six packs. They'll be larger boats, often carrying as many as 20 or more divers. You very likely will not be able to dive your own profile. In short, what I like to call least common denominator diving. Some divers find this to their liking, others do not.
As for Beaches TCI, they have large, good quality, well-maintained boats, and the dive staff tends to be professional & safety conscious, although I have heard a few hair-raising tales of screw ups. Last time I was there, they were experimenting with going to the better sites, e.g., West Caicos Wall, French Cay, but not I'm sure how frequently they are making the trip at the present time, if at all. However, I am sure not as often as Caicos Adventures that goes essentially every day.
Best regards.
DocVikingo