I haven't either.
I found their website: http://www.xigmatek.com/product_detail.php?item=13
They say it is: "a premium silent pump that maximizes water circulation allowing the base plate to stay extremely cool."
Odd as it's in the center of the rad which is a known deadspot. They should've mounted it offset to where the fanblades are. This would improve airflow over the pump and not have it sit in a deadspot. Different idea tho. Wondering how good it performs.