Acrobat has 3 versions: Standard, Professional and Extended
You'll only need professional version if you want to dedicate time to forms. You can create forms with the standard version, but the professional version comes with LiveCycle Designer, a tool created only to do forms.
The Extended version adds a special plug-in to create PDFs from PowerPoint. Of course, you can do it with any of the previous versions...but Adobe Presenter is like another program specialized on presentations and slick animations. It also has good manipulation of 3D objects.
That's why you've got different prices
Acrobat is the only tool I really know so I can't compare with other editors. I do think that it is worth the price if you work with PDFs frequently, and you don't simply view PDFs.