Appreciate your thoughts and experience. i'm also picky about where I hang my hat for a coffee and yes, haha I hesitate to recommend places I love in case it becomes so crowded I can't get in there anymore. Their willingness to go out of their way to make a dark roast coffee in small volume has won my devotion. It's rare and in a town that frustratingly doesn't make dark roast coffee, extremely rare. I did get to know the owner, but there was no "in", I contacted Padre and worked out the roasts via Messenger on Facebook. They were really responsive, polite, helpful, timely, communicative. I only met the owner when he hand delivered my first 1/4 kg of roasted beans to my apartment in Recoleta.
My own experience when I went there was that I was warmly greeted, it was well lit, airy, ample seating, the coffee roasters and main bar up front had a giant blackboard overhead full of technically oriented details on coffee. They're very specific on the origins of beans / coffees they offer. All encouraging signs for a coffee geek, I was in the right place and good hands. I didn't hang out there and on the street and around the corner there looked like interesting little cafes to take a coffee. I enjoy drinking mine at home