I just found out on one simple design, that I would have wanted to have concentric end caps on a part, but because of infill, it would have fallen in places.
I ended up using zigzag finish, and it prints fine, but lacks the visual appear that I wanted..
The perfect way for this piece would be able to use zigzag/lines on the first two or three layers on top, and then switch to concentric for the last one. Or possibility to have a single zigzag layer in between the sparse infill and concentric top.
I kind of like the earlier more, as I think the crossing lines will be more rigid end cap than the concentric one, as there is no crossing lines in concentric.