Notnard

It works fine. But it feels like a plastic attachment, whereas the Nikon grip feels like its part of the body. If you plan to keep it permanently attached to the body the Nikon grip is a better...

The small size and light weight of this gear should be an advantage.
Image quality should be fine. How well the focus captures action, we will see.

Serious money

http://www.amazon.com/Panasonic-H-HS12035-LUMIX-12-35mm-Series/dp/B00843ERMW/?tag=rumors04-20