You might like the Blue Marlin. Or if you want to dive the atolls you may want to look at one the atoll dive lodges such as Manta, Turneffe Flats, or Lighthouse Reef Resort.
As to Maruba, if you are looking to escape "commercialized," (and really by Caribbean standards Ambergris isn't that commercialized) I don't think Maruba would be the best choice. It's a very California-ized spa/resort, really not a jungle lodge at all. It does have good food, air conditioning, a nice pool and some exotic touches, though at a price.
If you want a remote and beautiful lodge, I'd suggest Ek 'Tun in Cayo. Or possibly Chan Chich or Lamanai Outpost in Orange Walk district. Or Pook's Hill near Belmopan.