Welcome to the forum.
The only difference should be that the trial is limited to 30 days use. All functionality works and nothing is watermarked Trial or suchlike.
The trial of the standalone version allows you to link to FrameMaker documents. It should not and that feature will be disabled if you proceed with the full version. Other than the time limitation, that is the only difference.
See www.grainge.org for RoboHelp and Authoring tips