Out of the gate I'll say I am new. However!
I use flash print and printed it wonderfully. Learning curved on the supports (used the tree one by mistake).
However I've tired literally all day to make this successful in S3D.
So far I've
*Change the Deafult Printing speed from 60mm/s to 30
*Primarily layer height 0.150, First layer being 135% of that for a (.21 base)
*Leveled the bed
*Made sure the bed was level
*Made sure again the bed was level, level, level.
Using ABS 1.75 Forge and Hatcbox with 35% fill in
The chamfer corner start to warp The cut outs along the spool holder fall down even though the its been supported in the cut outs.
Link to what I'm making. http://www.thingiverse.com/thing:714533