Previously I've used Office to PDF .doc and .docx files with very little loss in quality. Since I started using Spire.doc, I've noticed a few things occuring that cause me some issues. It seems there is no ability to set the Font Scale within Spire.Doc and this may be rolling into the PDF of the document. If the scale of the text is set at anything but 100% the PDF does not end up matching the .Doc file. It looks as though the scaling is not being taken into effect and all text is expanded back to 100%. The Character Spacing ability also seems to be missing.
Also I've come across Text Boxes located in the footer or header getting some interesting issues such as expanding to 2 or 3 times thier hight and loosing the lines around them.