In response to the OP, Just my personal preference - I don’t care at ALL about Ocean View from the hotel room, not at Casa Mexicana, not at Hotel Cozumel, not at ANY Downtown hotel. In fact, since I spend very little time in a hotel room when I’m not either sleeping, showering, or changing clothes, the view out the hotel room window means almost nothing to me. For me, the most important factors are comfort - nice bed, quiet and efficient AC, and a bathroom and shower large enough so I don’t feel cramped (my biggest bitch about the room I once got at Hotel Casona Real was a toilet in such a tight space that I had to lock my knees together to sit on it - NOT good) - and quiet enough to sleep comfortably. At Casa Mexicana, that means a room facing south, high enough up (4th or 5th floor) and far enough back from Melgar that street sounds are negligible.
I have stayed many times at Casa Del Mar - a long walk from downtown for meals, but more convenient for diving (it gives me an extra 20 minutes or more for breakfast if using a downtown Dive Op, as that is about the travel time for a boat leaving a downtown pier to get to the CDM pier), and the full-size pool is, at least for me, a BIG plus over Casa Mexicana’s kiddie pool. I like Casa Mexicana a lot, but I won’t stay there in the very hot months, July through September, because of its lack of a full-size pool. At Casa Del Mar, I prefer a ground floor garden/pool view room. The rooms at the back are standard rooms, facing the parking lot, and are smaller and, IMO, not as comfortable as the Superior rooms. I prefer ground level because it allows me to walk out the sliding doors to the pool for a quick dip without having to go through the lobby. Others prefer an upper floor room with a balcony for greater security for hanging wet scuba gear outside - although I have never had anything taken from my ground level patio. Entirely a matter of personal preference.