I just wanted to share my experience using the 'CAD Audio U7 USB boundary microphone' with voxcommando.
The microphone retails for about $70 depending on where you get it from of course, but I happen to get very lucky and found one new on eBay for $26.00 shipped. I was VERY close to buying an amulet remote, but I figured for the price I would give this a shot.
Upon plugging the microphone in, Windows 7 detected and installed everything on it's own which is always a great relief. It came with a decent length wire (10') but for my specific needs I bought a 30' USB repeater wire (about $13) to run it to a more convenient place. The microphone it's self is pretty sensitive, as it is designed to be placed on a table during meeting, it will pick-up sound from basically any direction including the vibrations from whatever surface it is placed upon. There are 'hang holes' (for the wall) on the back of the small pyramid along with a soft rubber grip across the entire bottom, overall the build quality is nothing less than excellent. I decided to give this a shot by hanging it on the wall directly behind my couch. While being behind be isn't the best placement, it does manage to pick up most of what I am saying. Since I use my android phone to control XBMC otherwise, talking 'against' the screen like the phone was on speaker mode actually bounces my voice back behind me directly to the microphone which not only greatly increases accuracy, but also creates the illusion that my phone is handling the voice commands (this amused me more than it should have). One issue I have noticed is it will tend to pick up audio or conversations and treat them as commands when they are not, but I have remedied this by making the 'listen' command "Computer start listening" to avoid unintended triggers. There are a few other commands I occasionally have issues with, but all of them can be remedied by tweaking voxcommando.
At the end of the day, I thought the strange little triangle on my wall would feel intrusive, but it now feels like it belongs where it is and it ACTUALLY GETS USED! I can't tell you how many times my hands were full or I was eating and didn't want to dirty-up my touch screen and this thing has performed fantastically.
PROS:
-Well priced (I got a very good deal, but honestly for the price this feels like a professional piece of equipment)
-Accurate
-Solid as a rock
-USB
-No additional drivers needed
-Omnidirectional
-PC/MAC compatibility (not too relevant here, but good to know)
-Low profile and sleek design
CONS:
-The little blue LED light is actually pretty bright and BLINKS while the microphone is listening. Fixed with a small piece of electrical tape.
-Sometimes a little sensitive and gives unintended results, but basically all can be fixed with software adjustments.
Hope this helps anybody looking into purchasing a microphone! Keep an eye on eBay for them, one can usually be scooped for about $40.