This is the second time I stay at the Principe Lisboa. The staff is very nice and helpfull, good complimentary breakfast (lacks only eggs, bacon and sausages) but with quality and variety of food.
Rooms ar clean and comfortable. I specialy apreciate the quality and comfort of bed and pillows. The hotel has a nice bar located in the lobby with fair prices and no extra charge for room service. The car parking is also not expensive (around 7eur/day) but the hotel do not reserve space even if you ask for it. they charge you for internet, but since you pay only 65,00 eur/night, I think it is ok.
In front of the hotel there is a metro station, so it is easy to go to historic centre and cheap.
Regarding taxi, any ride cost you around 6/7 eur. Pay much attention if you cach a taxi from airport as some times taxi drivers are not honnest. A ride from airport to the hotel cost you no more than 15 euros.
Nearby the hotel there is a big shopping center and some good restaruarants. One not to miss is the Colina. Fantastic portuguese restaurant and not expensive. The reception staff of the hotel told me about it and is much worth to go.

I've been in Principe Lisboa for five days, with my wife and my 3 y.o. son. The hotel is just in front of the metro, in a very good location. Quite easy to reach the airport by bus, which
stops in Saldanha, some 400 m from the hotel.
Decent breakfast (maybe this is the only thing that could be improved) , clean room and reasonably confortable (considering the baby cot, which took his space...) professional staff.
All in all a good value for money: I'd consider booking there again, should I need to stay again in Lisboa.

clean enough with the usual 3 star facilities- could not really think of any really bad points apart from its location for food and bars. Friendly barman and staff and not in the tourist begging areas. Just yards from the metro and for or five stops on the blue line to the old town and bars but beware you will get pestered by beggers that dont take no for an answer. A taxi ride from the airport is around 7-10 Euros in September 2011 However the first one we took charged us 40 Euros! We have done this journey several times now and know the first time he ripped us off big time! Get a price first. The hotel was fine though.

The location is very good, it is across the street from the subway station which gives you access to the 2 main lines. It is also very close to the El Corte Ingles (a huge mall), but the room has an old-style without any decoration, it is very simple. The breakfast is also simple with coffee from a machine. I think I could find a better hotel for the same price.