Greyhound sucks. Never again!
Chinatown bus made me think I was going to die throughout the trip.
Megabus are OK but it is still a bus and cramped quarters for that long start to get to me.
I am paying the $45ish each way for train from here on out. Sure, it costs more but the room you get, more comfortable seating, fewer smelly people and expediency are worth it to me.