I recently received a 100$ gift certificate to a local camera store and i was planning to get a 420ex flash for my canon XT, but they no longer have it in stock. I don't want to spend the 100 extra dollars for the 430EX so he reccomended the nikon sb600. Would this be a wise investment? He said one of his co-workers used this flash with a canon and had pretty good results. I know he is trying to make a sell, but is this true?