I have been a user of Maruti Ertiga VDI since Sept 2012. I must say this is the best value for money car in the Indian market in this segment.
Positives:
Great Mileage: 18 to 18.5 KMPL within City and goes upto 20 KMPL on highways
Great Service: Varun motors provides good and prompt service with home pickup and drop
Great handling: Rides like a small car, gives the comfort of a big car.
Great 7 seater: I have traveled with 7 members multiple times and its an absolute joy with no negative impact on either mileage or Air Conditioning or handling.
Great Sound insulation in the cabin, it is not as noisy as the other diesel cars
Negatives:
Needs a bit of practice to generate power since the engine is a turbocharged engine, you have to maintain an RPM of about 1500 in each gear for optimal power.
Arm rest for driver is not there, I got it installed separately.
Music system is just about OK for Music enthusiasts, those who like boom, should go in for external speakers.
Given a choice, I would have gone in for ERTIGA ZDI but it was at a higher price, but even that model is a very good value for money with its rear wiper and defogger, Automatic climate control, Dual air bags, height adjustable driver seat, steering wheel mounted audio controls and alloy wheels.
Go for ZDI, it will cost only INR.40, 000/- more but the value for money is very attractive.