The flat is just wonderful, extremely clean, spacious, cozy, comfortable and fresh.
Located in a great area, too: very close to the centre, but not too close to be noisy (because the very central streets of Porto can be quite loud at times).
Daniel is a friendly, hospitable and caring host: he met us, spent a good hour telling about Porto and giving some tips, and then also helped us with a personal issue, despite being busy.
Strongly recommended - the best experience I've had with rental flats.