Handling
With its tighter turning circle, the Toyota is definitely sprier than the Scion xD, something to consider if you do a lot of city driving; on the flip side, remember that a vehicle with a tight turning circle may feel a bit twitchy on the highway.
Drivetrain
The Scion xD has a more sizeable engine than the Toyota Yaris. Remember that smaller engines typically get better gas mileage, but smaller engines can be stressed more.
Utility
Neither the Yaris nor the Scion xD has a marked advantage regarding seating capacity.
Convenience
You'll definitely take the Scion xD for a fill-up approximately as often as the Toyota Yaris.
Comfort
While the front cabin in the Toyota Yaris offers a bit more head room than the xD, there really isn't much of a difference.
While the rear of the Toyota Yaris offers a bit more head- and leg-room than the Scion xD, there frankly isn't much of a difference.
Dimensions
The Toyota Yaris and the Scion xD compete for the same parking spaces.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. It costs approximately the same to get the Scion xD to the dealership as the Yaris.
The Scion xD won't tax your gas budget substantially more than the Toyota will.
The Scion xD doesn't pale in comparison to the Toyota Yaris regarding gas mileage.
The Toyota is significantly less expensive than the Scion when it comes to MSRP.
Warranty
The Scion xD and the Toyota Yaris have the same basic warranty.