This airport, over-all, does it job and does it well with a little character too. I've gone in and out quite awhile now but what I miss the most is the perplexing but hilarous succession of the dinosaur/george washington/steelers player statues. It was like a bizarre yet probably accurate history of Pittsburgh.
The "X" layout is convenient once you're past security. It's nice that the food and shops are centralized, especially when I run into friends at the airport. Even though our flights are in different terminals we can still chit-chat over qdoba or coffee. However, I think that taking a tram just to from security to your gate is a little unnecessary and serves as a quick fix, not a real solution.
Security usually takes awhile too, since everyone is checking at security in the same location (as opposed to larger airports with multiple entryways). In fact, I've never had a "speedy" experience here.
All in all, great choices of food in the middle of the X (like Ben and Jerry's) and who can argue against free Wi-Fi? My only other complaints are that I wish the three AmericanAirlines gates didn't have to be all the way at the end of terminal D... always such a walk that I have to look forward to, and secondly it'd be nice if the 28X arrived/departed more frequently.
Oh random, but I also like the news ticker thingy.