I stayed at Seven Seas (for 7 days) for my first trip in late August/early September (18 days total) and loved it. The location was perfect and the staff was very helpful and nice. Our bed wasn't the best but the owner actually called us after he read our comment card about it and told us that new beds were coming soon. I would highly recommend them anytime.
We went to Banana Beach looking for another place for the remainder of our trip and found it too Americanized for my taste (I like to stay places that don't remind me of home) and too far from town. The rooms were nice and the staff curtious but just wasn't my cup of tea.
We ended up at the Mayan Princess for $55-$60 a night(can't remember exact total) and found that place to be awsome also. They have kitchenettes in them also.
Just soak it all in and make the best guess you can...It's Belize...You can't go wrong!!!