I have to say it depends on destination and luck. I used to take Greyhound between NYC and DC/Baltimore. First of all, more often than not it was running late. Second of all, yes, lots of passengers there are not really pleasant to sit next to. Plus I had quite a nasty experience (on my way from Boston) when the guy next to me tried to assault me (which he stopped when I told him that I'm calling to police now). I didn't take the Greyhound ever since.