I stayed at Carolina's place for a month during July and it was amazing! Carolina was very friendly. My flight was delayed and she was waiting for me at the apartment. She gave me a great introduction to the area about restaurants, supermarkets and so on. Whenever I had a question during my stay, she answered really quick and helpful.
The apartment is super nice! It is very chilled (compared) to the hot Barcelona summer outside. It is in the middle of El Born, so of course you can hear people at the streets sometimes but that was perfectly fine. I would recommend this apartment and Carolina as a host anytime :-)