Check out the August 2006 issue of MA page 135..

They have an article on the rubber ducky antennas complete with test results done by Berg..

the ducky lost 4-5db overall vs a whip but was LESS directional than a whip..

interesting result was a whip pointed directly at the reciever lost 25db (99%) of it's signal strength vs at 90deg to the reciever.