We spent an afternoon on a Kerala backwater boat. Actually the accomodations were really quite plush. Great bedroom and bathroom. I am sure we were probably on one of the better boats. There is an Oberoi boat there as well, not a barge and it does longer trips, that is very very nice. We did not spend the night. I had problems with the food at lunch as there was little choice but I experienced that anytime I was out of the main Taj or Oberoi hotels.
India is a such a mix with some of the absolutely BEST hotels and then situations like this. A place you must go first class.