We have had our Sonic LTZ with 1.4L and automatic for just over 3 months now and have close to 8000 miles on it. So far no problems whatsoever. We are a retired couple (67 years old) and feel comfortable in this car.
Gas mileage has been very good with 38.7 mpg reading on the car display and we also check it the old fashioned way and get similar results.
It is a fairly quiet car depending on the road surfaces- some coarse pavement causing noticeable road noise but wind noise is low even on the interstate highway.
Handling is good but as one or two reviewers mentioned potholes or certain road irregularities can cause some darting.
We had 15 inch alloy wheels and Bridgestone Turtanza Plus tires installed at the dealership before we even took possession of the car. Past experience with large wheels and low profile tires (the LTZ model comes with 17 inch wheels) has shown that gas mileage suffers along with ride quality and we gladly gave up the supposedly better handling for the better mileage and ride.