For good and inexpensive I like Papi's diner on the North end. They have a little bit of everything. Ambergris Delight has an awesome conch pizza for something different and they deliver!!! Jambel's Jamaican Jerk pit is my personal favorite. Estel's is good too. There are so many. Elvi's was pretty good, but a little on the high side.
As for a room with a kitchen. We always go that route. We like having a leisurely breakfast in our "jammies" or sipping coffee on the porch or dock watching the sun come up. Some days I am perfectly content to lay in a chair on the beach, read for a while, watch the world go by, nap, then munch on my own tuna sandwhich. I just don't feel like going anywhere. I like to cook, so cooking the fish we caught and experimenting with new foods, spices and with recipes from the locals was fun for me. It's so much cheaper to have a fridge too, and buy your own beer, water and soda at the distributorship. The fruit down there is awesome, so we would load up and toss it in the blender with some rum and take the blender down to the pool. Yum! and totally heavenly. We prefer a kitchen.