Scanning files directly into Word can cause problems. IIANM, Word converts the scanned file to a BMP image. This image can lose resolution, making the image difficult to read, enlarge or print.
It also depends on the final use of the scanned document. If it is scanned for archive use, putting it in a program you know will always be available and readable is paramount. Word may not be the best option, especially if, five versions from now, support/backward-compatibility with your current version goes away. Same thing applies to Abobe Acrobat/PDF format; a newer version may break your current files.
Our office scanner will save files as PDF or TIFF. TIFF was developed for document management and in some ways is better than PDF. It is readable in most graphic viewing software, which means there is a large base of programs (not just one or two) that can read the files. The format is now under the control of Adobe.
If the file is to be used on a web site or sent to others, PDF format is probably the best due to the proliferation and freely available Acrobat Reader software. The software easily embeds into any(?) browser and is available, for free, for Windows(Vista/XP/2K/95/), Mac/Apple and all(?) versions of Linux. You can never guarantee that someone has access to Word, but everyone has or can get software to read a PDF file.
Dewey Williams