The Turim Alemeda is a clean efficient hotel and although not exactly central, the metro link to the centre is so smooth and frequent that this is not a problem.
Our room was on the 7th floor and was quite small but was one of the few in the hotel to have a balcony. Breakfasts were excellent and the desk staff were very helpful and willing to try to answer any queries that we had.
The hotel is easy to get to when arriving from the airport. If you take the airport bus #91, you can alight at Saldanha ( there is an overhead display in the bus, so you will know when to get off). Then walk back the way you came, cross to the other side of the road and take the street called Avenida Duque d'Avila. Just keep going and you will eventually see the hotel on your right-hand side. It's probably about a 10-minute walk. (On the way you will pass a Pingu Doce supermarket which you may find useful later).
To get into the city centre, turn right when you leave the hotel and go to the Alameda metro stop. Five very quick stops takes you to Rossio, in the centre of the city. On your first day buy a 24-hour card, which you can top up daily. This gives you unlimited use of the metro, the trams and the elevadores and is superb value. There is a ticket machine just as you enter the Alameda station, with instructions in English.
When returning from the city, some people mention the "steep" hill up from the Alameda station to the hotel and suggest returning via Saldanha metro station instead. Unless you are unfit, I think the problem is exaggerated and in fact, it's a much shorter route back to the hotel from Alameda. But everyone is different and you can make up your own mind about this.
Finally, to return to the airport the simplest way is to catch Bus #22, which actually passes the hotel. To get to the bus stop, turn left as you exit the hotel and walk back about 100 metres. There is a timetable at the stop so you can check out your times beforehand.
Lisbon is a super city with lots of atmospheric areas to explore. I would recommend particularly taking the tram out to Belem, riding the "tourist tram" #28 ( hop-on, hop-off using the 24-hour ticket) and visiting the Castle, but there is plenty more to do.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC