I have the Continental Pure Contact on my Volt and they have been great for traction, especially in wet and snow. I have seen about a 20% range loss at first and now down to 10% or so after several thousand miles.
The treadblock on these tires is noticeably thicker than either the Ecopia's or Goodyear FuelMax I considered for that car. Due to this difference, I expect they'll run for significantly more miles than the Goodyears I had previously.
My Leaf was purchased with cheapo Walmart Nexen tires which I'll probably keep for another year. I don't recommend those!