Our stay at António's was amazing! We got to Porto really early and he allowed us to check-in earlier (since our room was already cleaned). He communicates really fast. Helped us to choose a beach and also checked the public transportaion to get there.
The flat is superb, really comfy, it has all you nead and it is close to the center.
We even found the best estaladinho (pastry) in Porto close to the flat ;).