Yes, from my experience the iB's have better Airport reception then the PB's.
For example, in my APT my iB's Airport signal is ALWAYS full on (4 bars). With my PB it fluxuates from 4 to 3 bars.
My guess, it has to do with the Plastic housing of the iB VS. the aluminum housing of the PB --- but who know.
Anyone out there?
Peace!