Jon was a good host! When I got troubles so I arrived late he was waiting me without any problem. He let's use you things like coffee, salt, sugar, oil etc. so you don't have to buy it for just some days. It's a good thing that you can cook in his house because many hosts in Barcelona don't let you use their kitchen. The house in total is clean.
Just be aware that in summer it gets very hot, as the flat is in the 5th floor. To add you can here the gulls sometimes so it might be recommended to use earplugs. To the beach you have to walk 25 mins which is ok for some days. For going to the city take the metro of course.