With Megabus you can travel from city to city. Megabus is a pretty luxurious experience with outlets and Wifi. The prices are unbeatable and they also travel to many smaller US cities that are otherwise inaccessible.  I think that Megabus is more desirable than greyhound because of their marketing and aesthetic. Their two-story busses and bus designs are more fun. Although, the two companies share similar amenities, Megabus is more desirable.