We just had 5 super days in Mires apartment.
The location is good and within walking distance (15 min) of the Rambla and plaza de Catalunya. Moreover it is located just next to a Metro.
Mires is very attentive and addressed the issues that we had quickly (minor ant attact).
The Balcony is indeed nice and the main selling point of this apartment. Moreover we enjoyed that the kitchen inventory was new. The apartment is used only for rental, so it was a bit limited on kitchen supplies.