It was a pleasant stay, Vanja welcomed us and gave us many tips what to do in Lisbon. Everyone who I communicated with was nice and helpful. The apartment is not situated in the centre, but it is accessible by metro or you can even go by feet. The view from the 10th floor is wonderful.
Just be aware of the 250€ deposit (which is returned if everything is Ok) and make sure you have enough money on your credit card.
Also the electricity went out few times eg. when we were cooking and the washing machine was on at the same time or even if more than two hobs were on simultaneously, which was quite inconvenient.
But overall we enjoyed our stay in Lisbon.