From most accounts of those who own one GM built a really nice vehicle in the Chevy Volt. Customer satisfaction is very high, though you'd never know it from all the negative press surrounding the vehicle. Most of the problems that are causing poor sales of the Volt have to do with the GM marketing department, not the engineering and production departments. GM tried to sell their plug in hybrid as if it was an EV, while at the same time pushing range anxiety and "more car than electric", which backfired when people thought the Volt was a 40 mile "EV" that cost $40K. GM also made a mistake by marketing it as a Chevy product. What they should have done is market it as a Cadillac, an upscale plug in hybrid, throw in a few extra luxury bits, and charged an extra $5-$9K for it. In short they should have made the "Volt" the "Converj" right from the beginning.
The Cadillac brand could have handled the price premium better, and the styling is a little more aggressive and exciting. By not pretending to be an EV much confusion could have been avoided, along with much negativity. People would be less inclined to criticize a $45K+ vehicle from Cadillac than a $40K vehicle from Chevy.
Of course what they really should have done was build the real EV that Bob Lutz initially wanted to in the first place, but once that idea was scrapped they should have positioned it as an upscale luxury hybrid and badged it as a Cadillac. Next time GM, check with me, you could have avoided this whole mess.