The form asks you to comment on a dozen or so specific parts of the report and the working group proposal. I imagine comments submitted this way will have more impact than a plain letter since you will be guided to address all of the contentious parts.
https://www.icann.org/public-comments/ppsai-initial-2015-05-...
Scroll down to "Template for Responses (if desired)." (Direct link: https://s.zoomerang.com/s/VTLNGF5 )
The form asks you to comment on a dozen or so specific parts of the report and the working group proposal. I imagine comments submitted this way will have more impact than a plain letter since you will be guided to address all of the contentious parts.