It was great! My fiancee and I stayed here for the month of July and we found it perfect for the purpose. We were working during the week and exploring the city after hours and over weekends and this was ideal for that. Being on the edge of Gracia and Eixample (a stones throw from Passeig de Gracia) is the perfect location to be able to get into the tourist centre easily but also be more on the local side in Gracia. Loads of shops, bars, and restaurants nearby.
The apartment itself and the amenities were clean and in good condition and it had everything we needed. We had an issue with the hot water and internet but Monica was very responsive and sorted things out proactively (PS the internet was good enough for video meetings and streaming). The balcony is a great little space for enjoying the weather. Aircon is a must for Barcelona's summer so it was good to have this here. It doesn't reach all the rooms evenly but it cools the whole apartment down (with the exception of the walk in closet/"dedicated workspace") so, in my opinion, it gets the job done.
Again, Monica was extremely responsive and proactive so I could not be more positive about her as a host.
In general, I would highly recommend this apartment.