I get confused regarding which are the Treetop suites at Portofino. If they are the "duplex" suites, with two units side by side in a cabana, I'd say Mata Chica's are considerably bigger and more appropriate for a honeymoon, as they are true stand-alone units.
The regular beach cabanas at Ramon's in my opinion aren't as bright and cheerful and classy as those at Mata Chica or the larger units at Portofino.
My bias: All in all, I think the condotels on Ambergris -- Xanadu, Banyan Bay, Banana Beach and others -- offer more space and nicer space, about the same amenities and usually lower prices than most of the regular resorts.
--Lan Sluder