I have used Greyhound a couple of times and it worked out OK, BUT: two things you should be aware of :
1. Their max insurance limit is $300 bucks
2.They have no way of telling you where the package is at any given time, ie, they can tell you when it left the bus station, but for a couple of weeks after on my last shipment, they were not able to tell me where it was. It finally arrived at destination, but scared the beejesus out of me, as I knew I was only covered for 300 bucks if it got lost.
I'm not sure I would use them again, for the above reasons.
Just my 2 cents-
Mike O