Automate office files to PDF

Most office files are created with Microsoft Office and quality of conversion is defined by the degree to which it is the similar to what this suite creates – at least for visual appearance. What limitations do alternative converters have for Word, Excel or PowerPoint documents? What about emails created or received with Outlook? What about information beyond appearance: e.g. text encoding for search, tagging or metadata? Are there differences in quality of PDF code in general? Which solutions provide the best stability for automated conversions?

A vendor neutral presentation with as many answers as I can give.