OpenType (.otf) fonts typically have additional features that can only be accessed by programs that support them. OpenType works best in software like Adobe® Illustrator® and Adobe® InDesign®.
Although Microsoft Word 2010 supports some OpenType features, not all characters can be accessed if the font has a massive amount of alternates.
If you'll be using Microsoft Office programs heavily, we suggest you select a TrueType (.ttf) font when possible. While OpenType fonts will have basic functionality in Microsoft Office programs, they do not embed well in Powerpoint.