I always get a little too excited when I find a bar in Pittsburgh that specializes in cocktails instead of pitchers of Yuengling. This place is adorable; the aesthetic is charming (like a bar had a baby with an old london library) and little details like grandfather clocks that house bottles of booze instead of pendulums plus secret doorways in the bookshelf that lead to the restroom add to the ambiance.
The bartenders take their time making the drinks (good in most cases; annoying when it gets more crowded) but the concoctions are often unique and made with quality ingredients. They really should be considered "mixologists" for their ability to create a custom drink based on each individual customer's personal preferences. They do classic cocktails like the Dark & Stormy very well, too.
My only complaint are the prices ($10 for all cocktails); like many have said, it's more akin to New York or San Francisco. Of course, in Pittsburgh I'm used to going to bars where the drinks are cheap because the intention is to get hammered on many of them. This is not one of those places, so in the end it all kind of evens out.