The unified rear triangle doesn't make the difference with pedal bob. The pivot location is what is critical. The URT may help with frame stiffness. The other issue in comparing Bob with the birdy and Moulton is the difference in Travel. The significantly longer travel of the birdy suspension will add to the bob.

Pedal induced bob is created when the chain is not pulling directly into the pivot of the rear suspension. The larger the angle the larger the pedal induced bob.

The other factor in Bob is the rider induced bob which comes from the up and down movement of the rider----this adds significantly to pedal induced bob especially with longer travel suspensions.