Martin Lormes

Set Aside lets you change the post format on all posts in a category. This should come in useful e.g. when you used to run a theme that styles posts as “Asides” based on categories, and then you switch to a theme that styles them based on the post format, a feature which was introduced in WordPress 3.1

Set Aside

Change the post format on all posts in one category. Useful when you switch from styling "Asides" based on category to the new post formats.

dreamreal

Often, when a long block of text is being written, secondary content not 
germane to the paragraph in question is relevant, but out of scope of a 
given paragraph.
<pre><code> For example, this is text explaining that the author is using
 far too many words to be useful.
</code></pre>
This plugin allows users to write [aside]commentary[aside] and have it 
rendered appropriately.
<h3>History</h3>
Version 1.0 
 – First release

Insert Callout

Adds a sidebar comment (an inline box that includes commentary text) to a post

Set Aside vs Insert Callout