Sb-900 SD-9 Battery pack??? Worth it?

[MrSleepin]

i'm looking into getting a battery pack for my sb-900, and i wanted to see if anyone here has experience with the sd-9 or a cheaper alternative...?

i need it for skateboarding sequence shooting.
the website is very vague on the performance increase when using the battery pack.

http://www.nikonusa.com/Nikon-Products/Product/Flash-Brackets/4952/SD-9-High-Performance-Battery-Pack.html#tab-ProductDetail-ProductTabs-Overview

 

[Big Mike]

I've worked with Quantum Turbo SC units. They worked fairly well, but they weren't perfect.
The photographer who owns them, recently bought a new Quantum, I think it's the Turbo 3. Battery life is supposed to be much better and more important, the cable has a locking attachment, so it won't come loose when you're moving around.

http://www.bhphotovideo.com/c/produ...truments_T3_Turbo_3_Rechargeable_Battery.html

 

[MrSleepin]

anyone else?
i really don't want to spend over $100 on a battery pack.