Miguel was waiting for us at the appartment, although it was already quite late and our plane had been delayed. He left us after a quick tour of the place and some tips on restaurants nearby.
The appartment itself is very clean, large enough for me and my girlfriend. The bathroom is brand new (the whole place seems brand new!), and the kitchen is fully equipped in case we wanted to prepare lunch or dinner there.
Overall, the neighboorhood was rather quiet, but still lively. Conveniently located near the castle and Alfama district, 10 minutes walk from Rossio, 20 minutes from Praça do Comercio. In case you don't want to walk, the metro is 5 minutes walk as well.
The appartment is quite high up the hill so you need to be in good shape, but it should be ok for kids for example. Anyway, Lisbon is just hills everywhere so you better not go there if you can't stand a few (lots of) steps.
We were there in the middle of summer, and the place was quite cool during the night, which was a good surprise!

Given the price, I wouldn't think of a better place to stay!