You may also want to post this to the "Amtrak" forum, as there might be some folks that read that one but don't read this one.
Anyway, the pros of traveling by train:
*It's relaxing
*It's easier than driving (especially along the east coast)
*It can be cheaper than flying (in coach; though that depends on the specific circumstances of when you travel, when you book, what deals are available, etc.)
*It's an experience that can't be duplicated by any other mode of transportation (and I mean that in a good way; you can eat in the dining car and get to know your fellow travelers, it's more comfortable than a bus, plane, or car; you can look out the window and see the country from a perspective not available from the air or the highways)
*There are probably others that folks can add
Cons:
*It takes longer than flying (if time is important)
*Delays, especially due to freight congestion, can slow down your trip
*Due to inadequate funding and lack of equipment, the schedule choices aren't always the greatest