I'm really glad this thread came along...it got me thinking about where I was with my Comcast service.
I didn't even know that Comcast had a faster hi-speed plan I could switch to?....they do....and I did!
For $7.00 more a month I'm now at over 20mb download speed, and 3mb upload speed.
I downloaded a complete Linux operating system in under 10 min. (it used to take 30-45min).
I'm fast, and grateful :-)
Dave