vivitar slave flash

[Aharami]

is this flash any good? It's dirt cheap and Im thinking of picking one up just to have it and supplement my 430 EX, but will it work with my XSi?

http://www.1saleaday.com/

 

[The Stigenator]

its an okay flash for 10 bucks, not too powerful though. I its guide number is in the teens.