User blog comment:Mineko Charat Lucky/MtG LoL - Shauku, Endbringer/@comment-46.61.71.192-20130114135700/@comment-28016818-20130115164633

As for the lifesteal part, by looking closely you can notice than since W is an AA buffer, it will proc with lifesteal instead of spellvamp. The amount can help to compensate for the somewhat huge cost of the W.

Note that I went as far as recommending gunblade on my TIB...