I just purchased my (used)Caliber two days ago, so I cannot comment yet on reliability. I have the 2.0L CVT, and I am very pleased with the gas mileage and performance so far. I did not buy this car expecting great amounts of power - I bought it for the fuel efficiency, space, value for money, and looks (in that order). I drove the Mazda 3, Chevy HHR, Chrysler PT Cruiser (which I have owned before) and the Toyota Matrix when comparing. Although I had it narrowed down to the Caliber and the HHR (based on the issues listed above), I chose the Caliber over the HHR because of the final variable of value for money - the Caliber was 2K cheaper, and offered most of the same features as the HHR.
Roomy interior, fuel efficiency, sporty looks
As with others, wouldn't mind a little more oomph. Plastic trim inside and outside looks and feels cheap - better quality on that next time. Wish 120V plug would stay hot when car is off.