We have a FAQ page that consists of one page. We try to keep it optimized for longer tail phrases, but also wanted it to be easy for the user. We didn't want the user to have to keep going back and forth between pages.
On the other hand, if your subject matter is diverse enough and can be grouped together as the others have suggested, you will probably get a better
SEO benefit.
Keep the users in mind and design for what is best for them.
cd :O)