Originally Posted by
Lalato
They reference how testers felt about the ride... so it's not just comparing specs. They break things down to five broad categories and grade the bikes on 5 point scale in each category.
Folding, Portability, Braking, Hill climb, Cruising
Pretty good list. Ride quality would be another, but is more subjective and also very dependent on tire size, and maximum fit range for the given bike.