Compact apartment with amazing views across the city to the Douro river. Bring your hiking shoes as it's a long way up at the end of a busy day sightseeing.
One to thing to be aware of, which is obviously not the fault of the hosts, but there is a very loud nightclub near the Palacio de la Bolsa whose music carries! Seems to be the weekends but it kept me away until 4am Sat night. Great if you're going to be in the club... less so if you fancy some sleep.
Otherwise, can't fault the apartment or the company.