Overall, this was a great little flat! It's located in El Poble-ec, a 10-15 minute walk from La Rambla street (main tourist area). Great location for experiencing Barcelona outside of the "touristy area".
There's a very yummy pizza place downstairs from the flat, and lots of tapas places and our favorite little cafe, Spice, just around the corner on Carrer de Blesa.

The flat is very nicely decorated and the bed was very comfortable. Despite your neighbors being very close, we were never disturbed by anyone inside the building. The noise from the street can get a little loud as there are a few bars around, but other than a busy Saturday night, it was fairly quite. A/C also worked well, although you are responsible for emptying the water jug outside the window approximately every 24 hours.

Jon was a gracious host and met us at 1am after 3 hours of flight delays.

A few negatives about the flat - it's on the 5th floor, so you have to walk up a lot of stairs. I didn't remember reading that in the description but I may have missed it. If you don't do well with stairs this would not be the flat for you. Also, the hallways are very rundown looking and there's a large hole in the door to the flat (to push the keys back through upon check-out). We were initially concerned about our safety given the appearance of the hallways and doors, however, it was a very safe building and neighborhood. We never felt unsafe.

Another negative is the hot water. After only about 5 minutes in the shower, the hot water starting going out and after about 2 more minutes, the water was completely cold. Leaving my boyfriend with nothing but cold water. I don't think it unreasonable to have enough hot water for 10 minute showers. This problem should be addressed.

Lastly, my other negative would be the 30 Euro late check-in charge. I was made aware of this prior to our arrival, however, I don't agree with it based on the fact that flight delays are out of your control. And 30 Euros seems quite high.

Other than these few negatives, we really did enjoy our stay at the flat and loved our time in BCN!