Last weekend I headed down to Portland on the BoltBus. If you're interested in seeing what the buses are like and a quick review, I've written it up and posted it up with pictures on my blog: …blogspot.com/2012/…more
Short story: A good option for getting between the cities, but not without some small issues. For $1, it's a great deal. For $8-15, it's a good deal, but once the tickets get up to $20-25, Amtrak starts getting competitive again, if you can get cheap tickets. Traffic can cause delays, especially if your bus is scheduled to arrive in the afternoons.