I wanted to comment upon this car experience as a rental.
I have to say, this car impressed me. Considering General Motors' lackluster performance with small cars in the past (i.e. the dreadful Cavalier/Sunfire duo, Saturn Ion), the G5 was impressive.
The 2.2L Ecotec 4 is a very quiet engine that is only audible during acceleration below 50 km/h - after that, the engine noise disappears. Maybe there is too much wind noise, but the sound of the engine disappears after 50 km/h.
The powertrain is also fairly fuel efficient considering the horsepower available - it seemed to top off at around 6.5L/100km based upon the trip computer (with the four speed automatic). The engine also has great amounts of low-end torque, which is sadly deficient in the Corolla. The transmission is equally smooth - GM still can build transmissions without the annoying shift clunk famous in Aisen transmission found in Toyota products.
Handling-wise, it reminds me of a Corolla - probably not what Pontiac is envisioning as competition for the G5, but... it is a capable car.
However, despite the powertrain accolades, it is very evident once you get inside where GM has cut costs. The dash plastic is hard, with a low-quality feel. The seat material is equally poor, which reminds me of the seats in my friend's old 2000 Toyota Corolla VE (base model). Having not driving a higher-spec G5 (this car did not have power windows, locks, keyless entry, nor ABS), I cannot comment upon higher-spec model seats. As well, the driver's seat lacks lumbar support. The seat is especially tiring during long drives. I must say that the red back-lit gauge cluster is quite nice during night-time travel - much easier for eyes than white or blue-lit instruments.
As well, the car lacks a certain refinement in controls. The temperature rotary controls don't have the refinement of the ones in the Corolla, and the radio buttons seem to lack the tactile response as of those in the Corolla. These comments refer directly to aesthetics, and one's aesthetics may differ from mine, but the small components that make up the driving experience do have an effect upon the overall satisfaction.
I am only comparing the G5 to what I consider to be one of the class-leading compact cars available - the Corolla. The models from Japanese manufacturers still seem somewhat more refined than the domestically-produced small cars.
The G5 is a good car in the class - but nobody could convince me it is one of the best models in its class and price range. It is, like I indicated above, a dramatic improvement over the Cavalier/Sunfire, and a much better product than its sister-mate, the Saturn Ion. I only hope its excellent powertrain can stand the test of time.