The location of the hostel is perfect if one seeks to spend the days near the water. Nice promenade along the river. Cheap supermarket across the street. Beach was "under construction" in June and by the looks of it it may well be for a few more weeks...
The best part of this hostel is definitely the kitchen terrace which offers a fantastic view over the river - never been in a hostel with a better view I guess. Equipment of the kitchen unfortunately is very rudimentary. The breakfast is pretty good, only it is not served before 8.30 am. The journey from the hostel to the international airport (bus 504/ underground) takes no more than one hour.

The youth hostel (pousada de juventude) is, as the other reviews say, quite far from the centre of Porto, but there is a regular bus link from right outside the hostel and taxis were also very cheap to get home at night.
I stayed here for 2 nights in a private twin-bed room, which had a balcony and a beautiful view of the mouth of the River Douro. The room was comfortable, and looked like it had recently been refurbished. It was all very clean, as was the ensuite bathroom. I stayed in a few youth hostels in Portugal, and this was one of the best - it's modern, and our room was quite stylish in a minimalist way.
Despite the distance from town, it was still good value and much better than another Porto hostel I stayed in in terms of cleanliness, facilities, noise etc.
I would recommend this hostel, but be aware it isn't in the centre!

The Youth Hostel is near the Porto Foz, where the river meets the sea. It's 3 km from the town center, we took the bus often, it´s a 5 minutes travel.The view of some rooms is excelent, the furniture is new, my room was clean with a big window and balcony facing some trees. The WC is big and clean, the showers could have been better. It has a TV room, kitchen and snack machines. The staff is ok. Overrall its an average plus youth hostel.

I'll start with the good points, just to be fair:

The location is great, with the waterfront about 2 minutes walk, beaches within 15 minutes and some good restaraunts nearby. A short taxi ride into town is very cheap, or is walkable for the more athletic.

Bad points:

The room was very dirty, the bed was FULL of fleas (or other bitey insects), the staff were incredibly rude, and we had a broken fuse box in the cortner with wires visible. None of these things are unheard of in hostels and so arent my main source of complaint. The racist graffiti that covered the walls was what really got my back up. It wouldnt be hard to paint the rooms occasionally. On the same theme, the hostel was surrounded by graffitti supporting the NAZI party. Not only that, on the outside walls of the actual hostel there were slogans for "white power" and "heil hitler" and plenty of NAZI swastikas. This was totally unacceptable, and very easy to fix. I would reccomend that people find another place to stay in the city, as the price didnt reflect the terrible hostel, and it wouldnt cost much more to go waaaay up market.