The tighter Y seat pitch and width being used more and more even in widebodies makes it sort of academic whether I'm on a larger or smaller mainline jet...the in-seat experience isn't likely to be much different in many cases.

Some of the RJs are dreadful (e.g., the CR2 aka Devil's Chariot) but a few can be decent. Personally the single seat side on the ER4, particularly the exit row, is one of my favorite Y seats across the board.