Tender makes cocktails extremely well, has a fantastic selection of modern and classic cocktails to choose from, and a solid liquor collection (e.g., PVW 23). My favorite cocktails are the Corpse Reviver #2 (gin and absinthe) and the Vieux Carre (rye whisky and cognac). They have excellent lighter stuff as well. It takes a while to prepare these cocktails. On busy nights, it can take more than 30 minutes. The food consists mostly of smaller plates of appetizers with a gourmet twist on low-brow local specialties.
Of the bars in Pittsburgh, Tender has one of the best atmospheres. The interior is decorated in a 1920's bank theme. You sit on comfy sofas or around the bar at white leather chairs, and the lighting and sound level are comfortable. Cozy, but you can still have a conversation. Definitely good for a night out with friends or a romantic date.