I have all the same questions, so looking forward to the answers!

I tried 3 kinds of motion activated faucets, and ordered the Brizio Vuella. That was the least sensitive, and the type the salesman encouraged. Given what this darn kitchen redo is costing, this felt like cool splurge. My hands so sticky with dough, it will be nice to pass hands through and have water turn on.

I'll post back when installed.

Add me to the list of those needing more info on the motion activated faucets. Brizio seems good as does the Kohler. Over in the cooking forum there was a thread where a few of the regulars raved about theirs. That said, no one has long term experience past a couple of years. Online reviews are few and far between.

I chose tapmaster and love it! Touch free water and touch free garbage (Ikea's utrusta) at my new prep sink are the best things about my kitchen.

http://ths.gardenweb.com/forums/load/kitchbath/msg0415370826701.html and many other threads on GW

Here is a link that might be useful: tapmaster

I have the Moen motion sense and I love it. It works very well. The batteries are in a little pack mounted under the cabinet - easily accessible.
There are three options for turning it on - the old fashioned way with a handle, waving your hand above the faucet to turn it on and keep in on until you again wave your hand above the faucet, or having your hand or other object directly under the faucet, in which case the faucet stays on only until the object moves away.