The flat is a lovely size, bright and airy - perfect for two people and has everything you could want, including washing machine, modern kitchen etc. Very close to Casco Viejo, which itself has fantastic transport links in and out of the city.
We stayed during a heatwave, the flat has no Aircon but despite this, it stayed a cool comfortable temperature - it has large shutters to keep out the midday heat, and large windows to let in the cool air at night.
It felt safe and in a quiet location. Saying that, it's about 30 seconds from grocery stores and very close to bus/metro links.
Please note - if you follow Google Maps to the flat from Casco Viejo station, there is a steep hill, however there are lifts, escalators and buses that avoid this. We were also provided very clear directions by our host on the best way to get to the flat.