The best way to make editorial comments in versions of Adobe Acrobat prior to version 10 (version X) is with the Text Edits tool, located in the Commenting toolbar. With this single commenting tool you can indicate that text should be deleted, replaced, inserted, highlighted, or have a note attached.
But look high and low in Acrobat X, and you'll be disappointed. In the Annotations panel you'll see separate tools for deleting, replacing, inserting, highlighting, or adding a note to text. But the handy all-in-one Text Edits tool is nowhere to be found.
As it turns out, they've merged the functionality of the TextEdits tool in Acrobat X with the Selection tool.
Just select some text with the Selection tool, then ctrl-click (Macintosh) or right-click (Windows) and choose Highlight Text, Cross Out Text, Replace Text, or Add Note to Text from the context menu that appears.
Once you know about the functionality of the Selection tool, you won't miss the Text Edits tool. But it's sure disconcerting when a familiar workflow is turned on its head!