Airtime is defined as the feeling of weightlessness or negative g-force, when gravity is perceived as zero and having no effect on riders.
Enthusiasts divide airtime into two categories - floater and ejector.
Floater airtime is the general feel of weightlessness, while ejector airtime is definitive negative g-force.
Detonator runs on a pneumatic system, where the ride gondola is launched at speeds faster than gravity, creating ejector airtime for riders (remember, ejector = negative g-force). S&S launch towers operate under the same basis.
Intamin drop towers in comparison do not use pneumatics, and let gravity do all the work. Since gravity is pulling the gondola and the riders at the exact same rate, riders feel floater airtime, not ejector airtime, as they are weightless.
As a result, Intamin drop towers actually have a longer period of sustained airtime than their pneumatic counter parts, as gondolas continue accelerating until they reach the brake run. Pneumatics, while they start out faster, slow much more quickly as well. As the pneumatic gondola slows, the ejector airtime ends as well.
Of the two many enthusiasts seem to prefer the Intamin freefall drop tower over the pneumatic launch, as is made evident by top picks in this thread.
To claim that the bigger Intamin towers get, the worse they are is false; higher drop towers means longer periods of sustained airtime.
