Around here 90' in most cases is not enough to reach the city sewer. Also around here most of our mains are 6" just a few feet past the building foundation. From experience the 7/8" cable is a tad undersized for 100' of 6" sewer so if I was to use a sectional machine it would be the 1 1/4" cable and the K-1500 (my personal favorite machine is the K-500)
As to doing a better job than a drum, I disagree. Each machine can do an equal job. I find sectionals are good on grease and sludge blockages due to the open coils help stir up the sludge and get it moving again. For heavy tree roots, the drum is better suited since I can build up the torque needed to cut out the roots.
As I said before each machine has a time and place. It does not hurt to have both types of machines at your disposal. My preferred machine for 99% of the jobs is a drum machine. But I do have a large variety of sectionals for the 1% I need them on.