I have driven 23000 kms, and am happy with car. For first 2000 kms I used to get 15 to 16 kms mileage for full tank cng, now am getting 23 to 26 kms per kg cng based on my speed and weight. Among the people, it may vary but minimum 22 kms per kg I am getting.
I am happy with mileage but car body quality not upto mark, I am having Lancer and, compared to Lancer body Ertiga body quality is less than 35%. But it's good for mileage.