I am writing this prior to my upcoming NY trip because I have used their services before. What is nice is that you can call them ahead of time if you have questions. The number can be found on their website. I have learned that if you have had an injury such as a foot they will accommodate you by giving you a manual inspection without having to remove your medical boot. You must request this however.
It is also interesting to note that Pittsburgh International has a 2nd checkpoint on the far back of the landslide terminal. You can be redirected there if the main one is busy.
TSA pre checks are great provided you get it noted when you check into your flight. You don't have to remove your shoes and there is less you need to take off. TSA pre checks come if you fly first class or if you wish to purchase it. Unless you do a lot of flying it is not worth the money. Sometimes you will get lucky and get it for one leg of your trip.
The lines at Pittsburgh international are not as bad as in other cities since there is less people. I have found to obey their instructions and you will have no problem getting through. The staff has always been professional and helpful to me. Just give yourself enough time to check in so you can be at your gate in time for your scheduled departure.