Clean and efficient, two key characteristics of any good airport. Several shopping options for local products, like the macaron stand, and Commonwealth Press, in addition to a gourmet food market reflecting options at the Strio District (dried pastas, etc)
TSA Pre Check is fast, better than my former choice - the alternative security checkpoint. Food options have increased over the years I've been using this airport (2004). I mostly fly Southwest, which is what keeps me flying into PIT instead of CRW which would be a lot closer to my usual destination on the east coast.
Employees are reasonably friendly, and I appreciate that a bottle of water at GNC or Rite Aid costs as much in the airport as it would at one of these locations anywhere else in the area.