Dear Uday,
There is no considerable performance changes b/w these two. But I use "set_table_for_first_display" because it is newer and mostly seen procedure these days.
"Reuse_alv_grid_display" is bit old and "set_table_for_first_display" is on OOP. and has more features.
REUSE_ALV_GRID_DISPLAY is a Function Module and SET_TABLE_FOR_FIRST_DISPLAY is a method of class ref to CL_GUI_ALV_GRID.When using the class, it is meant to be used inside of a custom container in your screen, so you could have more than one.
Thanks
Tharaka
