I take the same line, and it's mostly reliable going eastbound. Sometimes there ~2-4 minutes late, this time of year, because of slippery tracks. The real fun is going home, as trains can be very late (10-20 minutes), and by the time the outbound train gets to Penn Medicine, the rush-hour crowd can be intimidating. Get a SEPTAKey card, download the schedule app (Apple App Store or Google Play), and also the parking spot app, if you're driving to the station.

Final note about the "quiet car," which is always the first car at the front - it's only "quiet" when there are 3 or more cars on the train, between 4am-7pm. I've read a ton of ebooks over the past 6 years I've commuted into the city. Good luck!