We have found more often than not that the water will be rough outside the reef and the boats are typically smaller than other dive destinations. You have to do a back roll entry usually and then take your gear off in the water to reenter the boat. Maybe I'm just too much of a weenie, but I prefer a nice big 46 foot Newton dive boat with real ladders when the water is rough.
There is a lot of marine life to see and Belize is the only place I have seen a Manta Ray in the Caribbean. One you are under water Belize is a great place.
In my 15 odd years running up to 3 dive shops simultaneously on Ambergris Caye, and operating over 12 dive boats 25-55ft, and a mixture of rear entry and backward rolls I have to say, from a safety aspect the backward rolls were by far the safer boats, for diving Ambergris Caye.
I actually got rid of my rear platform boats, as I considered them dangerous for all but experienced divers that could de kit and exit the water quickly while taking into account the heavy swells and the rear of the boat slamming down in between waves.
Yes diving from Ambergris can be choppy and since the majority of divers that visit Ambergris are novices to intermediate vacation divers i found the rear platform boats to be difficult and dangerous for these types of divers in choppy conditions.
Balancing on fins trying to hold onto a rail while ajusting a mask and trying to keep balance at the back end of the boat as it is being tossed up and down is challenging for most divers using a platform boat from Ambergris Caye.
As for exiting its the same story with platform boats, in 8ft swells (not uncommon in Feb march) its very difficult and dangerous for divers to get back on the boat with the boats back end going up 5-8 foot and then slamming back down as a diver tries to hold onto the ladder and remove fins.
The best boats IMHO and experience is the side entry backward roll from entry and the ladder over the side for exciting the water, this way you have no chance of being hit by the back of the boat as it is rolling up and down in the swell, additionally the diver has plenty of time to remove his gear before safely climbing the ladder onto the boat. ( You would be surprised at how unfamiliar most divers are with there kit)
Platform dive boats are excellent for calmer waters but for Ambergris I would get a newton with side doors for entry and exciting
Gaz Cooper