Hmm...
Chevy Sonic: 28?30/37?40 mpg, ???? lbs, $14,###, ? interior volume unknown, 138hp
Hyundai Accent: 30/40mpg, 2400 lbs, $14,195, 89.7/13.7 ft^3 volume, 138hp
Toyota Yaris: 30/38mpg, 2300 lbs, $14,115, 84.4/15.3 ft^3, 106hp
Ford Fiesta: 29/38mpg, ???? lbs, $14,000, 85.1/12.8 ft^3, 120hp
Mazda2: 29/35mpg, 2306lbs, $15,635, 87.1/13.3 ft^3, 100hp
Honda Fit: 27/33mpg (or 28/35 auto), 2500 lbs, $15,175, 90.8/20.6 ft^3, 117hp
Kia Rio: 28/34mpg, 2,365 lbs, $12,300, 92.2/11.9 ft^3, 110hp
Nissan Versa Sedan: 27/36mpg, 2350 lbs, $11,000, 94.3/13.8 ft^3, 109hp
Nissan Versa Hatchback: 26/31mpg, 2700 lbs, $14,380, 94.3/13.8 ft^3, 122hp
Note: I skipped other manufacturers due to lack of participation in this market segment...unless I missed some models, which is possible. Chrysler and Dodge don't seem to have anything remotely similar. Mitsubishi and Subaru don't seem to have anything with a competitive price or fuel economy. Suzuki doesn't come close to these MPG numbers.
Whatever the weight, Sonic's FE is on par with the other cars in the segment. Depending on how accurate those provided estimates are, it may be near the top or may be middle of the pack. Horsepower shares the top spot with Hyundai. Sounds respectable enough to me.
That Nissan Versa sedan's price is surprising, and its interior space somehow equals that of the Versa hatchback.