I traveled from Air India Pantnagar to Chennai, via Delhi. I had bookings on two PNRs and it was not an issue to book my bags through to Chennai. Last time out(on the same route) this did not happen. The flights were on time and the food served on the Delhi-Chennai sector was lovely! The staff were vibrant and made the journey comfortable.
One issue was, the aircraft is too small for a busy sector as Delhi-Chennai and that too, the last flight out of Delhi. Air India used to fly a A321 on this flight and of course, this was vulnerable to inordinate delays. Looks like Air India is working hard to redeem its position.