As you see, the T1 line is the same both ways. Also, the speeds are often guaranteed. Cable/DSL speeds are usually just guaranteed 'up to' the rating.
Comcast has a 'gold' service that is currently 6000/768. Both that and the regular are in the process of having the down limit being bumped up by 2000 (to 6000/384 or 8000/768.) Some other cable services offer 10M or higher download speeds.
DSL speeds most commonly vary depending on your distance and line quality.