I've got a Concept 20 bat and it's superb.
It's pretty much the same profile as my GM Neon, same handle and blade length but extends a bit more into the toe and has a bit more of a fuller profile.
For a 2.9 bat the thing looks huge, although when I measured the width it was 105mm wide. Even more shocking was the fact my neon was 103mm!
Both great bats, the Kook will eventually become my Neon's successor I think.
The handle on the Kook feels a lot fuller than their handles of the past few years and had a pleasant oval shape on the bottom hand. The silicone grip feels spongy, very grippy and works well. The knob on the end (apart from me) is just an enlarged version of a standard handle end and didn't affect pickup but does feel nice when you're giving it the long handle treatment