I'll come back later and post more. We've had a Chevy Volt since the end of February. Got it in NJ. We love it.
Only extra is a wee bit on electric. Our first month was about 14 bucks more than the bill from the previous year (same month). I'm sure it'll be more. I've read 1.50 average per night as a statistic.
Gas is dirt cheap.
We use about 3 gallons a month so far.