My girlfriend has taken the Boltbus a couple of times. If I remember correctly I think she paid something like $15 each way. The bus had wifi which she thought was nice. She's pretty picky, so I think if it was ok for her you'll be fine as well.

As far as safety concerns, I want to say that Boltbus is part of Greyhound, which is probably about as reputable as you're going to get in the bus industry. That's not saying much, but its something.