I am using this car for last 17 months for my personal purposes, and have used 34k KM, love driving this car, I have travelled from Chennai to Bhubaneswar (Without a night halt), Chennai to Hyderabad frequently, Chennai to Mysore but don't get the back pain, so seat is good enough for the driver. Performance is excellent, but I found the mileage is below close to 16.5 on the high way and around 13 in the city. The service centre guys also said you will get mileage around 13 to 14 in the city. That's actually bad.
Otherwise, the car is really good in terms of performance, seating, luggage space.
Hate the Maruti Service.