I had a very nice stay in Gisella appartment. It is small but very functionnal in a building with a 24h janitor. The neighbourhood is very nice with a couple of bars and a store at the corner. It is quiet (except on Friday nights) and safe. It is very close to Lapa (10 min walking), to the Center as well as the Central Station (Central do Brasil) from where you can catch the Metro or Buses. Yet this part is not touristic at all so you quickly feel as a real carioca (well not exactly but the feeling there). Gisella is very nice host. Initially I had a problem with the Internet that she very quickly fixed. Also the rent was very reasonnable since I was there during Copa do Mundo.
In brief highly recommended....