This review is only for the coffee & atmosphere - I have yet to try their food.
I love coming to this place to study/do work. I usually go to Starbucks, but I hate when I come out reeking of coffee. Peixoto provides a pleasant atmosphere in which I can comfortably sip a gourmet latte and the noise level isn't too high. I usually sit near the window - there are plenty of outlets.
One inconvenient factor is the bathroom that's out in the hallway, shared by multiple restaurants and the fact that it's not open late at night. But other than that, I really like this coffeeshop.