This hostel is not in the middle of all the Porto action--which probably helps keep prices reasonable. It is staffed by student interns and other young adults--which matches the guest demographic. There's a laundry a couple of blocks away. I paid to have breakfast included--lots of options, including protein (ham and cheese). There's a guest fridge, too.
Your bed will have an assigned locker--bring your own small lock or buy one from them. You can also rent towels if you didn't bring one. Walking tours depart from the lobby 3x a day, and you can get a glass of wine for only 1€ during the evening happy hour.
The hostel IS close to Torre de Clerigos and Livraria Lello (which has a Harry Potter conection). You can get to most everything else in 10 minutes of walking--15 at most. When you check in, the staff will offer to suggest things you might like to see or do (they will also offer a map). The hostel is uphill from most things you might be seeing/doing--wear comfy walking shoes!
If you are given a choice of bed, don't opt for the one just inside the room door, as the automatic light in the hallway goes on anytime someone steps out to use the bathroom. (At least one other hostel in town sells eye masks...). Also, be warned that Porto's "smoke-free building" definitions do NOT include the 30-foot perimeter we have in the US--expect some smoke to waft in through any open windows or doors.
Porto is an amazing city--enjoy your stay!