Today PR has the biggest advantage of spending almost all its journey time in its home..
Is puntuality the only criteria??
No,being a puntual train isnot a big thing as puntuality of any train completely lies in the hands of enroute controllers and it depends upon the aggressiveness of the train's schedule too..A train having huge slack will always be comparatively less delayed/more puntual or a good train like PR running almost completely in its home will always be expected as a puntual train...Even there are many passenger trains in IR which are...
more... very puntual..So,u can't distinguish SK with other trains in terms of puntuality but u can distinguish in terms of of that aggressive non-stop schedule and it doesnot lie in the hands of controllers too...I guarantee,even that most puntual passenger train will not have that aggressive non-stop schedule like SK but it may be puntual like PR..
In terms of puntuality,SK is nothing in front of not only PR but also lots of M/E/SF/Pass trains and u know the reason for that. :-)