The host (Theo) is very responsive and informative. Our stay is more impressive than what we expected. The house is located in a quiet residential area which is very close to a metro station and around 10-minute walk (700m) from Barcelona Sants Train Station. Although it's quiet, we felt safe walking at night as there were people walking around or sitting in a cafe/bar in the neighborhood. There are many restaurants, supermarkets, Orange network provider shop in a walking distance.
Theo's place is a very well-maintained and well-decorated old style house. It is very clean, very neat and fully equipped with kitchen utensils, toasters/microwave/oven, dish washing stuff, extra blanket/ towels, toilet papers. Just bring your own soap and shampoo. The 2 sofa beds were comfortable. Just a small note for travellers with heavy luggages, the entrance to the house (2nd floor) has a flight of ~10 stairs.
In summary, we have had a very pleasant stay at Theo's and highly recommend this place to travellers :)