My partner and I had a very comfortable stay at Helen and Andrew's place. It was a nice quiet room upstairs (I rarely saw the family, partly because I was out exploring the city). Location-wise, you are about 2-3 stops / 30 mins walk from where all the attractions are. Plenty of train and bus options for you at your doorstep. Area felt safe even when we returned late at night.
The room was clean and the bathroom was true to pic. We brought our own bedroom slippers which we recommend others do as well. LOVED the book and tourist guide collection. They also provided towels (even make up towels!) and toiletries for us.
We didn't really enjoy the balcony view because it seemed a bit complicated to open up the door, but that's more of our fault rather than the hosts who showed us how to when we checked in (we were out for most of the day). Loved that there was chips, beer and olives when we checked in. Helen and Andrew were very warm. I recommend that you read her Barcelona guide too if you choose to stay - we found that useful for us!