I've travelled via 12839 (HWH-MAS) Chennai Mail[in 2AC] on 30th May 2024. I'm literally amazed & pleased with the quality of service in this train. Absolutely neet & clean , washrooms were also being maintained properly by the cleaning staffs. We haven't tried any kind of food from pantry car. Last but not the least this train has maintained super punctuality though the train was delayed nearby 1+hrs in intermediate stn like BBS, KUR, BAM(delay makeup at VSKP, RJY, BZA) but in the end it reached Chennai Central 10min before the scheduled time.
There's no complaint against 12839 according to my journey experience.