Lígia & Luisa's apartment is lovely. It is well equipped, very clean and well kept with comfortable beds. They are both very helpful and friendly and gave us lots of useful local info. They were there to meet us even though we arrived late on a Saturday night and made us feel very welcome right away.
The building is on a small street in an old part of Porto, a short walk from the river. It is easy to reach all the tourist spots on foot but be ready for the hills!
I would recommend a trip to Porto, it's lovely and I would definitely stay in Lígia & Luisa's apartment again.