Review: (they have 3 locations, I primarily use the Fulton St. one)
Great shop with great people. I basically learned how to mountain bike from reading singletracks and picking the brains of GRBC staff.
Their focus seems to be split between road, commuters, MTB and Fatbikes. This is the kind of shop thats always representing at bike races and events and they give back to the community a lot.
They carry GT, Cannondale, Salsa & Surly bikes. They also have a big selection of Fat/winter biking gear as well as bikepacking-specific gear.
I demo'd a few bikes from them before buying my bike, I also bought 2 bikes for my wife there. Really can't say enough good things about this shop and the folks that work there. I always feel like they mechanics do a great job and will go the extra mile for you.