I'll recap that later, as well as my morning on the beach--and in the water--but with a few minutes to kill, I thought I'd commend (and recommend) the Mirasol Copacabana Hotel.
I booked the hotel on Booking.com with no external recommendations--I really miss Rick Steves when travel beyond Europe--for 3 primary reasons:
1) Location very close to Copacabana Beach
2) Location very close to a Metro station (though I only used it once)
3) Cost (not cheap but relatively inexpensive) and cancellation policy (my credit card was only charged the night before I arrived, and then for just 1 night (of 4)
Having frequently and happily stayed at Motel 6, I do not demand much from a hotel.
Beyond a good location and sense of safety, the room must have a decent bed, shower and toilet. Even in the U.S., the TV and other amenities are largely immaterial.
I don't know if I'll post a review on Booking.com or TripAdvisor, and wouldn't suggest this is a @@@@@ hotel in the vein of Four Seasons, Ritz-Carlton or the grand Copacabana Palace Hotel just steps away (not that I've ever stayed at such).
But beyond the room being perfectly satisfying and location being terrific, the staff was consistently superb--even if the English skills of a couple front-desk clerks weren't great--the free breakfast buffet was excellent and the rooftop terrace with a swimming pool was nice and offered great views.
So in my view, the Mirasol Copacabana Hotel deserves @@@@@. Though I'll still be here a few more hours.