said by nanoflower:But for what most of the people using the Internet do (web browsing/email/occasional picture/video watching) they won't see much difference between even 6Mbit and 50Mbit, especially with Powerboost. The higher bitrates are really only useful for people that need to transfer lots of data (even if for only short periods of time) like watching a movie, or downloading some big files. That's not your typical user if you believe what Comcast and the other ISPs say.
It's also beneficial to a family that has several users online concurrently or a person who has dozens of devices connected at the same time.