I didn't get to meet Sílvia, but she was very responsive and helpful, and everything was sorted out easily. The apartment itself is gorgeous: it's modern, cool and spacious. The location is great too, in the same block there are loads of restaurants, and a few streets towards north you'll find the hippest area in Porto. The closest metro station (regarding the purple line that goes to airport) is about 15-20min walk away, but apart from that the location is super handy, and feels more 'real Porto' than the touristic centre – which is still within an easy walking distance. Would recommend this place in a heartbeat.