Got my beat diesel PS (Base model and silver color) on April 13, 2012. Till data I have clocked 8, 300 KM. Believe me guys its doing unexpectedly well. I am getting an average of 22-23 KM/Litre, however I try to keep speed in the range of 60-70 (Most of the times AC remains off). Also done some 5-6 highway trips of 200 KM each and performance was amazing.
Overall, I can say that this is an amazing product from GM and nowadays after sales service is not a problem because over 2, 900 workshops are available on pan India basis.