i know this is like a what's your favorite caboose thread, but I have to say after 20 something years PS 1 and 2 are still my favorites. (I have all railking)
I guess I'm talking mostly about the sounds. and I know some people don't like sounds at all. But for the talking at idle and the uncoupler PS1 and 2 are still my favorite. PS3 locos are more detailed,and run smoother, they don't do as much idle talk and their couplers don't really make a sound, they just don't do anything for me