I collected my Nikon Speedlight SB-700 flash yesterday. I had it shipped from Boolchand (in addition to selling jewellery, they sell cameras and accessories) in St. Thomas. Cost $325.00!!! About two months ago I purchased another cheap (less than $100.00) flash (Yongnuo Speedlite YN560) but it was not a Nikon and I am yet to figure out how to take good photos with it. The photos had alot of light and I was not satisfied.
I met a gentleman a few weeks ago and we were taking about photography and we were discussing this same matter and he advised that I should made the investment and get the Nikon Speedlight SB-700. Well I can tell you right now I am very pleased. I did a few test yesterday in areas where the lighting is very minimal and the photos were great! Note: I have not read the manuel nor have I made any adjustment to the flash or camera.
Also with the other flash it was not stable on the camera but with the Nikon SB-700, there is a lever on the flash that allows me to stabilise it on the camera.
It is always advisable to purchase accessories like flash and lens that are manufactured by the same company that made the camera.