Utility
The Pontiac Vibe and the xD can accommodate the same number of passengers.
Dimensions
Your wallet will hurt more every time you fill up the Pontiac than the xD because of its bigger tank.
The Scion xD and the Pontiac Vibe compete for the same parking spaces.
Convenience
The Vibe's fuel tank will need to be replenished a little more often than the unit in the Scion xD.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. It costs roughly the same to get the Scion to the dealership as the Pontiac Vibe.
The Scion xD will save you money at the pump compared to the Pontiac.
In terms of gas mileage, the Scion xD has the Pontiac Vibe beat.
Regarding MSRP, the Pontiac Vibe costs considerably more than the Scion xD.
The Scion xD will save you a bundle at the pump every year compared to the Pontiac.
Handling
With their comparable turning radii, the Pontiac Vibe and the xD likely handle almost the same into and out of tight spots.
Drivetrain
Torque is the force that lets you accelerate quickly, and in this respect, the Pontiac Vibe isn't much more powerful than the Scion xD.
The Scion xD has no lessons to learn with respect to pickup from the Pontiac Vibe.
Comfort
Taller drivers will significantly enjoy the extra head room in the Pontiac Vibe's front cabin compared to the Scion.
The Pontiac Vibe offers more head- and leg-room to your passengers than the xD does.
Warranty
The Scion and the Pontiac Vibe have the same basic warranty.