This is a concrete rock on which I will plant three or four junipers in the spring. What works best for you aesthetically, the oval or round base containers? Here are two photos with the probable front and below a Dropbox link to a quick video giving it a 360.
I think it depends on the trees and the final composition. If it is soft and rounded then I like the oval to compliment them since the rock is fairly angular. If it is more sharp and angular then the rectangle. I think the round is a bit too small to look stable unless the trees are very small so it is distant view of a panicle.