We do not know if their claims of making the best burgers in Barcelona are true, but they do cook up some excellence. The two partners have a lot of experience between them: one was the chef at La Royale and the other was the maitre d' there. In their latest venture they make hamburgers that are created as complete dishes made into sandwich form. Try the excellent Mediterranean burger: tomato and basil sauce with toasted pine nuts, thick roasted mushrooms and parmesan.
The tapas are worth trying as well, they're not just there to look pretty. There's a very good Peruvian 'tiradito' (raw fish, similar to sashimi, in a spicy sauce), and you should definitely taste the croquettes – a very happy find are those of chorizo and manchego cheese.