Coming from the land of burgers (USA that is) and eating at hundreds of spots around the world, I…read morefeel fairly decently positioned to provide an assessment. It's a popular establishment here and what I can say is that the burger probably sits in the average category. It does not have the secret flavor touch of burgers from premium chains like Shake Shack or Five Guys. It is also far from some "gourmet" burger joints now found in many cities. I also can't even put it up to challenge some of the steakhouse burgers, but that's a different category.
At the same time, it is an good quality meat and a decent bread. The bread was both too squishy and too squished. I enjoyed the burger here, but cannot say that there would be a reason to come back had I lived in Santiago. The sautéed onions seemed way too sweet for me on the burger, but someone else might like it, so can't critique on that. The good part is that there are draft cold beers to chase the burger down and again, some pretty decent fries topped with cheese. People were nice, although a bit disorganized as they didn't realize we ordered a beer until I went to inquire.
If visiting the city, the spot can probably be skipped, but coming here is also not going to be a highly regrettable moment as it is overall a good meal.