Greyhound and other bus companies have upped the ante, in recent years, with the European model of luxury coaches with wifi and electricity. I haven't taken Greyhound itself, but since moving to NYC, I have opted to take BoltBus (a Greyhound subsidiary) to DC and Philly on all but one occasion. It is way cheaper than Amtrak or Acela, takes just about as long to get there, has wifi and electricity and picks up/drops off near the Amtrak stations in city centers.

For 2-5 hour trips, I will continue to choose the BoltBus/Mega Bus option. I know that they experience delays from time to time, but it's not too bad and getting a ticket for $15 is way more practical than a $50+ ticket on the train or a $100+ on an airplane.