I tried going the "Export to SVG" -> "Convert to PDF" route. Unfortunately, every app I tried for converting the SVG to PDF also had gradient problems!
What I finally did was: export to PNG with custom height of 2000, then embed the PNGs in a PDF (using Latex nd TikZ).
It would have been nice to specify the dpi setting instead of a custom height/width when exporting to PNG. Then different diagrams would get the same text size.
Anyway, thans for the great diagramming tool!