One of my ongoing annoyances with Microsoft Word is its inability to handle figures in a consistent way. The last quirk I discovered is the following: if you group a figure with a textbox — something often done for creating captions — the print quality of the figure decreases! PDFs are not handled correctly either for some unknown reason. In this document I put four times the same figure: twice as PDF, twice as TIFF on 300 dpi. One of the PDFs and one of the TIFFs is grouped with a textbox, and one isn’t. Just print the document and see the effect of grouping for yourself.
To make it even more interesting, you can group figures with textboxes, move them around, and as long as you ungroup the figure/textbox before you print (to pdf) the quality is fine.