I was working for Airtel for a year till March 2003 , after quitting my job I switched to a Hutch connection, Back then hutch had their network in 4 cities in karnataka, however now they have coverage in all major cities and towns of the state.
Hutch has wonderful customer service, there are some goof ups some times which is common in all cellular companies but they are fast in making that up. The pproblem with hutch is the coverage which is insuffecient to handle the load its customers offer, for example if you are using your phone in bangalore while travelling within the city you will notice that you will be disconnected at some spots in the city where the coverage drops. I can pin point atleast 5 such locations I know off.
They are the 4 th players in the cellular market and you would need a dual band phone to access their network , this was an issue earlier when single band phones were dominanat in the market but nowadays it all the phones are dual band if not tri band and hence this is not an issue.
If you happen to have a corporate connection with hutch you will have access to an exclusive customer support number which has less wait time and faster service.
I currently have three hutch postpaid connections and I am happy with all three of them. there have been issues with my connections in the past four years of my relationship with hutch but on every occasion hutch has been more then helpful trying to fix the issues.
In total I would say hutch is a decent player in the cellular market in karnataka who provide world class service, however they would still need to work on getting their network flawless.