If I am Travelling I will prefer Facilities Cleanliness then Speed of that train.
When I was in my trip from AGI to FZR and Back.
The Train I loved was Intercity Express AGI to GHY Punjab Mail NDLS to FZR then BCT Janta Express FZR to NDLS and then ISO Certified train of NFR aka Kamrup Express.
Worse train was Dn 12501 PSK...
more... and Up 12502 PSK between GHY to NDLS then NDLS to GHY. NoFacilities no puntuality but name also says Poorvottar Sampark Kranti Express First part Poor in also meadiums. I think Adh Assam is far better train than PSK after its extension to NTSK.