Quote: "so do you think the gadget is accurate; no trouble performing actions or anything?"
I found that when the movement was large enough, it was very accurate, but I doubt it would be very accurate at detecting finger movements as shown in the Project Natal teaser.
I haven't used it in quite some time so I can't be very specific as I don't really remember all that much.
Quote: "I'm wondering how I could use the thing to have a soccer ball kicked in the game....
"
It can detect leg movements totally fine, I did play a football game when I first got the Kinect, it wasn't perfectly accurate but I suspect it was a limitation of the way the software was written rather than the detection capabilities of the hardware itself. (e.g, the direction the ball moved would often be wrong for where you moved your leg). As for the micromanagement, well that depends how complex.
On the Xbox 360, you simply hold your hand above GUI elements for a couple of seconds to activate them.