I had a cool stay in Carlo's flat. Carlos was very friendly and welcomed me to explain the main sight in Porto, that was really helpful.
The flat is exactly like the pictures, clean and tidy, with everything you need.
The little garden at the back is peaceful and perfect for smokers.
I can't put a 5 stars rating because I just need to mention the flat is facing a road with traffic and it can be annoying in terms of noise; I would suggest to bring your earplugs.
Other than that, all good, perfect for a few nights.