“…Acrobat 9 Pro brings everyone together right inside document windows.”
Mac|Life magazine recently reviewed Acrobat 9 Pro, giving it a 4 out of 5 (great) rating. You can read the full review here.
The reviewer specifically mentions the collaboration side of things. Quote:
Collaboration gets a big push in Acrobat Pro 9. The Shared Review feature lets you upload PDFs to an internal server or to the new Acrobat.com website and invite reviewers anywhere to make edits and comments in a browser or the latest versions of Acrobat or Adobe Reader. Reviews aren’t real-time—comments and edits must be manually uploaded—but they aren’t bound to a single session. Reviewers can check for new comments and add their own any time they open a PDF marked for review…Running a Shared Review session that’s broadcast with Collaborate Live is an easy and powerful way to get a team working together—not to mention being literally on the same page.