The structural differences manifest themselves in each material's response to pressure:

Gel Padding Motorcycle Gel Gloves

PFM Memory Foam
GripSwell Motorcycle Cruiser Gloves

When compressed; gel, being a liquid, immediately resists and transmits the pressure, proportional to the force applied, in the opposite direction. This design simply transfers any forces on one surface to the other with minimal cushioning effect. PFM Memory Foam's open cell design creates a pressure distribution network through which air can move according to varying pressures on the surface. This creates a progressive elastic response that greatly dampens forces, which are typically transferred in a conventional design. The other advantage to the open cell material is that the collapsibility of cells under the greatest points of pressure allows the material to conform to anomalies of any surface allowing pressure to be even distributed.