During December-2011 - me and my family had taken a trip to Kerala through Nirmala travels. The tour manager was very co-operative. His name was Sachin. My overall experience was good throughout the trip. I think the trip is value for money. They put us in decent hotesl ( not three star or anything ) but decent and clean ones. Food wise - we did not find too much of a problem. It was clean and good food provided. Entertainment within the bus was also pretty good.
All in all - I would recommend Nirmala travels as an operator to travel with.