Anna's guesthouse is the perfect choice for a short stay in Lisbon. First off, its position is outstanding: you're as close as you can get to the Praca do Comercio, Rua Augusta, Rossio and Figueira while still enjoying the relaxed atmosphere of the Alfama. Amazing sights are quite near - the Sé is basically next door, the Praca do Comercio is five minutes by feet, the Miradouro de Santa Luzia, de Recolhimento, de Graca and the Castle of Saint George are all in a 15 minutes walk from the guesthouse. You can also catch the 28 Tram by simply walking for maybe half a minute!
As for the rooms themselves, what I enjoyed the most of Anna's rooms was that it felt like home. After a couple days, opening the building's door, getting upstairs and walking into the guesthouse's corridor felt like I had done it a hundred times before. To return home, tired after a long day spent exploring Lisboa and to get back into a homely place is not something to be taken for granted.
Everything was clean; never have I had trouble sharing the two bathrooms with the other guests, who were all very clean and quiet.
I'd definitely recommend it to any of my friends and would return here without a trace of a doubt.