There is some kind of divide between Camden and Penn, not sure if its cultural or something else. (I ride Penn 4/5 days, and Camden on my bowling night).

In DC, take your time walking down the platform to Metro after leaving a Camden train, and you're part of a laid-back bunch. Do the same thing from a Penn train, and you'll be run over (if not physically knocked off the platform).

That doesn't explain the seating issue though - but this might. Camden trains have traditionally been the older single level cars, so those riders may have been appreciative of anything remotely newer than what they had, while on the Penn line, you are actually losing amenities w/the new cars (like arm dividers, head rests, and legroom).

This plan won't work as the front of the train going south is the back of the train going north. So, on one of the two trips you'll have a bad seat.
As far as the difference between Camden and Penn, I thik it has more to do with crowding than anything else (I ride Penn daily and Camden is my back-up, usually in the evenings when Penn breaks down; therefore, I ride it often).
The Penn line is much more crowded, as bad as it is for standers (I stand every evening from DC to BWI and about once a week in the mornings), sitters also aren't very comfortable due to have standers leaning on their seats or using their seat to keep from falling or having standers fall into their laps to let ticket checkers and late people getting to their car by. So, to add an uncomfortable seat on top of it, just makes things worse.
On the other hand, the Camden Line people are much more likely to get seats and not have someone hovering over you the entire trip. Also, yes, they are more used to uncomfortable seats than Penn Line riders.
I must say that I agree with MTA's decision to get the cars on the tracks and save time and money and just go with these seats. However, let's not make these seats the new norm but only the price we pay to have a lot more seats a lot faster.

I love the new cars and seats. The ride of the new cars is very smooth. Seats are angled better for slightly relaxed yet firm ride for the back. Additionally, the distance between seats is just perfect for putting knees against seatback while using laptop, sleeping, etc.

Tony - You can open your laptop in the new seats? I couldn't even open my hardback book all the way without having to lean it on the seat back in front of me. It was similar to the worst airplane seat spacing I've seen. Also I kept banging my knees into the seat in front of me. I must be taller than you.