The area right around the Sheraton is mostly computer shops, but if you venture just a little bit further, there are a lot of grand old buildings from the colonial era. The street behind the hotel has a lot of public busses, including one that goes straight to Miraflores.

I was very well treated at the Sheraton, even as SPG Gold staying on points. You have access to the lounge on the 19th floor even as a Gold. The lounge serves an excellent breakfast. There are snacks in the afternoon as well, but I would not go out of your way for them.

There is a mall right next door to the Sheraton. The moneychangers there have decent rates, so I would minimize the amount you change at the airport.