PRO: you have alternating layer directions that makes the part stronger
CON: the layer is not supported, and falls through the internal infill
With concentric external fill:
Pro: The layer is supported,
CON: stacked identical layer are weaker, plus the center ends up with an open slit sometimes
To have the best of both options, it would be best in this case to
1) have the first layer to be concentric to
provide the best support for upper layers.
2) and then the following layers to be rectangular.
Please consider adding an option "C" to the 'external Fill' pull down:
A) Rectangular Fill
B) Concentric Fill
C) Concentric First layer only (then Rectangular for following layers)
