Leo's flat is the best. It has all the amenities that you want and it is well kept. The two flights of stairs are no big deal. The towels, sheets and all linens are really clean.
The location is just fantastic... close to bairro alto, chiado, rossio. I mean, you can walk everywhere from the apartment. Many restaurants,bars,sights are all within walking distance.
Thanks Leo for being so accommodating, and for your flexibility.
I highly recommend Leo's flat to all of you looking for a nice place to stay in Lisbon.