My 4 friends and I stayed in Casa Tortilla over New Years 2013-14, and we booked on Booking.com via EasyJet, which was all very simple and all we needed to do was give credit card details as proof of booking.
It is in a perfect location, just a 3 minute walk from a metro station, 3 supermarkets, plenty of small bistros and restaurants and of course the Sagrada Familia.
The apartment itself is a lot larger than the pictures make it out to be, with it's own separate Kitchen, 2 bedrooms, a living room/dining room and bathroom with a shower. The apartment is very nice and has everything you basically need, including free WiFi. As a group of 5, we used the 2 bedrooms (one with a double bed, one with 2 singles) and the double sofa bed which was surprisingly comfortable.
The owner was very friendly and helpful with information on how to get to and from the apartment and airport, and his colleague was also very helpful. We paid a €150 damages deposit which was all ... mehr