As a non-native Pittsburgher, I would say the Sunnyledge brunch tops Grand Concourse. Not in the quantity, but in the service and the ambience. It's funny how often I passed by this place turning onto Fifth coming down from Wilkins, but didn't try it until my last weekend in Pittsburgh.
I came here on my last Sunday in Pittsburgh after I had posted a list of things I wanted to do before leaving. The Sunnyledge owner offered a deal and graciously gave the 4 of us a round of mimosas. Along with this deal, we had an incredible brunch.
The 4 of us were sat on the porch, overlooking Fifth which wasn't that loud. The brunch came with an entree and a buffet. I love perfectly-sized portions and this one was it. I had a lobster club sandwich which was great. The brunch buffet was held in a room in the lobby, which was quaint and small. Caviar. Small pastries. Just the perfect balance of sweet and savory. Even though the crowd here were a little more upscale and classy (one of the few places that I saw valet parking), I never felt that I was treated any less (I was a poor graduate student with a love of food).
The only drawback was that the tables and chairs were somewhat cramped. I had to struggle with getting out of my chair each time to go to the buffet. But this was a small negative compared to my experience at Sunnyledge.
I hear that Sunnyledge is known for their cocktails as well as their stay. Next time I am in Pittsburgh, I would like to try out the boutique hotel. But until then, I would highly recommend this brunch.