What we need is a review on this flash...I would not jump on this with out doing any research on it...
What would you recommend to use for a three light setup for flash 2 & 3 using speedlights? Your going to be using a higher end Nikon speedlight as the main.
I haven't found any actual reviews on this flash either, at least no reviews from the typical credible review sources. It is what it is: a dirt cheap flash from China, so there's not a lot to say about this flash. I have found some customer reviews, most of which are in broken English, and obvious biased endorsements. Although I have seen several customer reviews (that are less suspect) that boast how well built the product is. It looks like Curt has volunteered himself to provide a review, so you're in luck!
As for your question, I can't answer it objectively because your choice is very different than mine. My own opinion is that the Nikon flash line has a lot to offer in the form of TTL and commander modes for multi-flash setups. It's all very cool, very customizable, and also very expensive. Had I made the initial choice to go with a Nikon setup, I would very likely add Nikon flashes as #s 2 and 3.
That said...as you very well know, I do not own Nikon speedlights. Anyone who has researched lighting with speedlights for more than 5 minutes has stumbled across the Strobist site. This was my choice, and for good reason (if only in my own mind). But I can save that for another post.
