Manfrotto ML840H Maxima LED Panel

[Neilmac50]

I have a Nikon D3s along with various Nikkor lens and have enjoyed immensely its low light capabilities however I am getting to the stage were I would like a flash gun for certain subjects.Being a big Nikon fan I have been looking at there SB-700 flash gun as a reasonable step into this realm,I have been doing a little research and come across the LED lights that you can now buy.Knowing very little about them my question is are they a viable alternative to the conventional type? I have been looking at the above Manfrotto model and like the idea that it also can be used on a continuous setting for any video work that I do and it appears to be a similar price.
Thanks in advance for any of your replies, Neil.