if this is your first time in Rio, I'd skip Iguaçu, even though it is a great place to go. Plenty to do around here if that's your first time and your trip is too short to do both.

Sheraton is a good hotel, although not close (i.e., not within walking distance) from both the famous (Ipanema, Copacabana) and the best (Prainha, Grumari) beaches in Rio. There's probably a hotel bus, but you'll have to see this with them. Taxis are probably better options anyway.

Good trips nearby would include Petropolis (mountains, about 1 hour driving), Angra dos Reis and Buzios (beaches, two hours driving each). Depending on when you're coming, these could be great places to spend one night.

hope you have a great time here.

FR