Daniel's place is fantastic. It's in a great location, within easy walking distance to all the major attractions on both sides of the river. We ended up walking to the center of town, sightseeing, then across the bridge for some port tasting and back throughout the day. There are tons of cafés and restaurants and galleries nearby as well.
Daniel is an excellent host - he gave us a number of timely suggestions of places to eat that turned out to be awesome, places to go on a rainy day with a kid, and he was accommodating in every way possible.
Porto is a gorgeous city, and staying with Daniel made the experience that much better.