Have you travelled by Duranto Express trains ! How was your experience in comparison with Rajdhani and Shatabdi trains ??
Shatabdi runs for shorter distances - without involving a night journey. It has pre-determined official halts. You sit and travel throughout.
Duronto runs for longer distances involving night journeys. You can stretch, sleep and go. There are no offical stops between the originating and destination stations. Halts, if any, or for a brief time and for technical reasons.
Otherwise, in both types of trains, you get your refreshments served to you on your seat. Added comfort is in respect of bedding given during a journey by Duronto.
But otherwise, the journey remains the same. Not much difference.