I'm pretty annoyed at people trying to compare the ELR or the Volt to a Tesla, or Leaf, or any other pure electric. The biggest reason why I wouldn't buy a Tesla is because total electrics are still impractical. If you look on the Tesla website, you'll see that I'm basically limited to a 300mile radius to where I live. This is because at 300 miles, it'll take 4:43 to charge my 85kw battery with the supercharger. Bump that down to a 240v outlet, and its a 9:26 charge. And thats after spending nearly 95k for the car, because the 70k version only goes about 200miles. There are some tricks to get 80% 'fairly quick', but you're still adding hours onto each segment of a roadtrip.
Which is where the volt comes in. For -most- people, they only need 30-50miles a day in their car. BUT, if you want to take a road-trip just 5 hours away, you're going to want a way to get there without spending 4 hours charging. And at $299/mo lease, its cost isn't much different than some nicer compacts of its class, and for everyday driving you spend nothing on fuel.
I'm -my- use case, and driving style (where I go) -- I think given the choice of a Tesla or ELR, I probably would go with the ELR. At least then I wouldn't have to buy another car so I could goto the beach, out camping where there is no power, or any of the other places the 'supercharger' grid hasn't made it yet. But in reality, the volt is nice on its own, I don't have any desire to pay another 35k to have a neat badge and a blocky-looking car. Don't get me wrong, I think the Tesla is a nice car, but without the gas generator, its a non-starter for me. Now put a little Diesel TDI generator in there, and I'd buy a Tesla in a heartbeat!