Between driving out there for a roller coaster or two, visiting Cath's family last year and volleyball tournaments, I've driven the PA Turnpike I think four times in the last year. Every last time, I can remember being totally wiped out on the drive, especially the coming home part.
If it wasn't four hours of the trip, I think it might be scenic, with the mountains and tunnels and such. But there's a lot of hard lefts and hard rights. It's not like driving through Michigan where you can pretty much just drive on auto pilot.
I don't know of too many fans of the PA turnpike. I tend to appreciate it in that once you know it well you can pretty much mark your trip off by mini-landmarks... the varying rest stops, the tunnels, the electricity generating windmills, etc etc.
The Ohio turnpike is very different. When I drove across it in order to visit my brother in MI, I noticed the rest stops are all the same (however, much nicer) and the land is very flat.
I drove the entire length of the turnpike last summer, and I found it thoroughly exhausting. The scenery is pretty nice and the tunnels add interest. But all those curves and concrete barriers force you to always be "on".
I have to drive across PA on 80 several times a year and, while pretty boring by now, it is much less tiring. Fewer curves and the road is lined with trees on both sides (no concrete medians). and I always look forward to seeing the sign that reads "Trucks to Leeper".