We really enjoyed our stay at Isabella Y Lucia's place! The location of this apartment is great, the space was good, and it even had air conditioning, which none of the other European places we've stayed in had -- super amazing during the summer! There was also a washing machine, which was very helpful. Also, there's a Nespresso machine, so if you want to bring some pods (which we found to be relatively cheap in Barcelona) to make espresso, you'll have delicious coffee!
A couple of things to note about this place: The apartment is up many flights of stairs, which we (my boyfriend and I are in our 20's) were able to bring our suitcases up, but it might not be great for someone with limited mobility. Similarly, the shower in the apartment is sort of remarkably small -- again, my boyfriend and I did not have much trouble using it, but it might be quite difficult for larger individuals to manage. I'm a very small person, and my elbow repeatedly knocked the faucet and turned off the water while I was in the shower.
Overall, this was a really lovely place, and I'm glad we stayed here.