Reverting vandalism:
*Article comments: Sysop deletes page, user must notify sysop, or tag for deletion in some way.
*Talk page: Revert by user
Gathering concensus/discussion:
*Article comments: Threaded conversations, but these tend to diverge, hard to keep track - users can't relocate comments that are irrelivent to discussion
*Talk page: Can be edited in the normal way, section headers keep focus on topic.
Article end of life (deletion)
*Article comments: Deletion log entry (and RC spam) for each comment.
*Talk page: Deleted (1 page)
Removal of a comment that's been replied to:
*Article comments: Deletes thread that's been replied to
*Talk pages: Doesn't
Uselss chatter:
*Article comments: Fine
*Talk pages: Fine
Recent changes:
Article comments: Creates new page. No edit summaries
Talk page: Is a normal edit, can have a summary