Look, listen. I'm not an expert in traveling=) But with my small experience of 7 countries, I've never met apartment like this. This loft rooftop has huge windows and cool terrace. If you walking on the street and thinking that there are pretty noisie, go up to the apartment and you never hear what is happening outside. But climbing stairs, what was written here before, it's the truth - climbing stairs can be challenging. But if you like hiking or can visit Tibidabo only using only your feet - stairs are not a big problem. But still - keep in mind. Also, Ash is cool. Met me and my girlfriend, was kind, hospitable and interesting person to talk.
100% recommend staying at his apartment.