My Father loves his 2003 Matrix XR - although his girlfriend hates the black colour scheme.
He's really impressed with the gas mileage. His girlfriend drove to Vermont in it once and they were worried that the gas gauge was broken because it showed so little gas used. (The gauge was fine.)
It also carries lots of stuff, including a 14' long rolled up carpet (with the front seat down) and, on another trip, two IKEA 'Billy' fully assembled bookshelves. To be honest, I can't remember if the truck was tied down, but the point is that the car was able to transport these items easily.
He's up to around 90,000 kms on it and the only thing I've heard him say, as far as maintenance is concerned, is that he had to get the brakes done. He really thinks the car is SOLID.
I've talked to my own mechanic about the Matrix and he has nothing but good things to say about it. My mechanic is nursing my Mazda 323 along on a shoestring budget, so I trust his appraisal.
My father will be buying another Matrix in the next few months. He will be replacing his manual with an automatic, as he's getting up in years and finding manual transmissions less and less comfortable to use. He's not considering any other car, as he finds it so easy to get in and out of the Matrix and loves the reliability.
As a backseat passenger, I can make some comments: I don’t like the way the central tunnel (the drive shaft?) is so high, when a car like the Honda Fit can have such a low one. I think the rear windows are too small, too!