I had my Matrix XR for almost a year. I loved it and had only two minor problems that needed fixing (plastic piece on underside broke and my key would sometimes stick in the ignition). However, my car was recently totaled in a low impact (only about 15 mph) accident at a four-way stop intersection where the other car (a Jeep Wrangler) decided to proceed into the intersection after I was already halfway through. He hit my passenger side at a relatively low speed. However the damage to the side of my car was pretty extensive, mostly in the front passenger seat. I thank God my kiddos weren't in the car! Just watch the ratings and get side impact airbags if at all possible.
I love the overall look of the Matrix. I really enjoyed the moonroof. This car was easy to drive and really easy to park in small places.
Bring the safety ratings up. Make side curtain airbags standard, not an option. Reinforce the side impact beams more.