This is a great little cafe nestled in the boughs of the charming Polish Hill neighborhood - it has an excellent vibe, first-rate coffee/espresso, and a commendable menu selection replete with a number of vegan options. I really like the stellar artwork that bedecks the walls. Usually coffee shop art is tacky, banal, and/or amateurish - however, I've found all of the art on display in Lili to be both interesting and aesthetically pleasing. Lili's is the antithesis of an insipid commercial chain coffee shop - it's definitely among the best hangout spots Pittsburgh has to offer.
***Update: I recently went to Lili's, and I guess the artwork rotates regularly. The stuff I saw today was really really poor quality.