I had a MAZDA5 before the HHR. The HHR is a much better vehicle. The 5 had the MAZDA zoom zoom thing, but it felt sportier than it was.
The traction of the HHR SS is much better with less torque steer.
There is a lot more usable storage in the HHR, although the 5 was pretty versatile with the 3rd row seating and then fold it down for storage.
The HHR SS out accelerates the 5, out handles the 5, and gets 15% better milage than the 5.

 

Me too......