I think the Volt is a success in terms of meeting it's intended design parameters. However, I think the whole notion of the all-electric car and plug-in hybrids are flawed due to our current infrastructure.
As long as we burn fossil fuels to get the electricity, the electric car is just sweeping the fossil fuel/pollution problem under the rug by putting the "dirty" side of power consumption out of sight (back at the power plant). Also, there's no way our current power generation infrastructure could support even a fraction of the population switching to electric cars. California already has rolling blackouts - if people stopped burning gas and switched to electrics, the problem would get drastically worse.
I think electric cars are a dead end for the present...At least until our entire power grid makes large-scale switches to alternative energy, and there is no timeline for that currently. Also, there is currently no guarantee that practical fuel-cell systems will ever be truly affordable or mass-producable. The current offerings are all extremely expensive, proof-of-concept vehicles with short useful lives.
We'd be better off with diesels or diesel hybrids. People don't want to admit it, but those are currently our best options IMO.
I really wish I didn't sound so cynical, but that's the picture as I understand it.