If in Barcelona - and especially visiting for the first time with friends, I warmly recommend Piia & Fernando's apartment. It is situated in one of the coolest neighborhoods - Poble Sec, which has more of a local hipster feeling by not being suffocated with too many tourists. The place is quiet, simple and clean but has all the basics and comfort needed.
We rented bikes from a nearby local bike shop so getting to Barceloneta beach, wondering through the Gothic Quartier, or even reaching Park Guell by bike was super easy. The surrounding area offers many options for the evenings so you don't really need a tram or subway to enjoy good tapas and good wine - check the Blai, it's a street around the corner, or walk around in El Raval.
We met Piia when we arrived, and she is a very open, welcoming and I would say cool person.
When again in Barcelona with a group of friends, I will definitely try to book the apartment. We were 3 people, but the apartment fits perfectly 2 couple or up to 5.