http://wiki.ffxiclopedia.org/ http://wiki.ffxiclopedia.org/wiki/Blink http://wiki.ffxiclopedia.org/wiki/Aerial_Armor http://wiki.ffxiclopedia.org/wiki/Zephyr_Mantle
In short, they all technically give the same status effect, Shadow Images (which are different from Utsusemi Copy Images), but there are various nuances you may or may not want to be aware of. Number of shadows you get is a big one, and, as Lago (where's that video?) mentioned, Skill level may or may not be a factor, and in varying degrees based on the spell used.
Finally, the link at the top of this post is your friend.