Nice stay at the Bragas, not a palace but for the cost it's excellent value. Near the university district of Porto so lots of good places to eat and drink. About 10 minutes walk to Trinidade metro where you gan get to most of Porto. The walk is up a steep hill and gets a bit emotional carrying your luggage in the June heat!
Rua do Bragas is a little scruffy, and quiet late at night but didn't feel unsafe. There's an excellent cafe on the right down the hill from the AirB&B, good for brunch and morning coffee. And if you turn left at the bottom there's a pedestrianised street with shops and cafes and banks about 5 minutes walk away.
Check-in and out were both simple. The building is old and shows its age (cracked walls and stiff doors), but very clean rooms and comfortable bed, with cleaners coming every day. Towels and shower gel are both provided.
There's a good communal area with a well-appointed kitchen, washing machine and drier and a nice garden. Other guests were sociable and it had the feel of a more relaxed hostel with private rooms.
Its a bit noisy and there's a cockerel somewhere in the neighbourhood which starts crowing at around 5am, so bring earplugs if you're a light sleeper!
Overall I would definitely choose this if back in Porto and looking for decent accommodation on a budget.