It pleases me to see the many four-star reviews for Apsara, as it deserves to be better known as one of the top Thai restaurants in Pgh.
The reason that it does not have a packed dining room is the location. Yes, Carson St is a hoppin place Thursday through Sat night, but those wanting a great dining experience are not going to fight the South Side crowds, and parking, to go out to eat.
But, they should. Go, find someplace to park, and you will be so glad that you did. If Apsara were located in NYC it you wouldn't be able to get a table.
I can't wait to go back !!