I created a drawing with a few "modern style" boxes (the rounded-corner "shiny plate node with shadow") overlapping.
It looks okay in yEd, but when exported to an SVG (and worse, PDF), some kind of guidelines are visible in the drop shadows.
The SVG looks okay in Inkscape, but when I include it in a PDF document (created with LyX), the lines become visible.
Exporting a PDF directly from yEd causes very obvious artifacts when opened with Foxit Reader or Sumatra PDF (for some reason, Adobe Reader isn't installed on this PC so I can't test that). The mysterious drop-shadow guidelines (2 per shadow) are visible, and the shading on the upper-left part of the "shiny plate" modern nodes is broken.