For the past 14 months, I own a Nano and it is a fantastic car.
We have done over 13,000 kms and can safely state that buying a Nano is one of the best decisions that we have ever taken. Apart from intercity driving, our Nano has also done highway drives of 300-600 kms (in a day...) to neighbouring towns and cities. The high technology engine ensures a great economy and ample power to run at 90 - 100 km/h with a full load (of up to 5 full sized people).
A high ground clearance and excellent traction allows the car to drive on off road, rough track, on steep slopes and into axle deep water. The car has tons of interior space (even on the back seat with the front seat fully to rear position, or in the front seat, with the front seat fully to the forward position) and a great headroom - even large sized or extra tall people easily sit inside the car with great comfort.
The Nano has a powerful air conditioner and heating too. Getting into the car is a breeze - the large sized doors open wide and the base height is such that one has to only rest their rear onto the seat and swing the legs in - no crouching or getting into cramped spaces.
Power windows, central locking, cheap spare parts, a brilliant electrical system and a virtual maintenance free working - we could not have asked for more in the Rs. 2.3 lakhs we paid for our Nano.
Please feel free to ask any queries about the Nano from an actual (Indian) user.
Apurva