Both are nice I like that the second is cleaner and has a stronger impression but I probably go with the top one. Better centering top and bottom for one thing and the line in the left margin for another...
Top stamp is clearly better, and illustrates the dividing line between the panes.
The lower stamp looks decent at first glance until one realizes the remaining perf chads along the bottom carry a considerable portion of the stamp image. What would its centering be if the chads were picked out?
I wonder why the straight edge is not so straight? Note the gap between the straight edge and the center line. If entire pane was cut at that angle it seems to me that the cut would be into the stamp design a few rows further down. Don