We had wonderful stay at Luìs place. In my opinion, to really experience Porto you have to stay at one of its old buildings. And for that, I highly recommend this apartment. The building has its history (ask Luìs and he will kindly tell it), it is also close to everything best in the city and the apartment has everything you could ever need.
There are other cheaper options around, but it is only because they have no noise isolation and all nightlife of Porto may interrupt your sleep. Luìs took care of that while maintaining the authenticity of the building. And that is another reason why I recommend this apartment.