Banana Beach is a top property. Very nice 1-bedroom suites with kitchen. The 2nd and 3rd floor units on the water are the nicest -- you're just feet from the sea, with a balcony to enjoy the view from.
I think Captain Morgan's pool is nicer, but other than that, I'd say Banana Beach is the better property (I've stayed at both) -- far nicer beach area, friendly staff, beautiful rooms. Also, it's nice not to have to take a water taxi into town anytime you want to go.
Belize First Magazine http://www.turq.com/belizefirst/