I picked mine up last week and I'm very impressed with it. It's "The Club" on steroids. The alarm is super loud, blinking lights are visible even with tint and the unit seems rock solid. I got mine on sale at GI Joe's for $59.99.
A local police department gave away 600 of these to the public one day last week because car thefts were so bad in their city. I didn't make it to pick up a free one, but I feel that the price is worth it.
I know it's not the only answer to car thefts, but in my opinion it along with my alarm and common sense parking tactics, I feel a little more secure than I did with "The Club".
One thing is that the siren is so sensitive that if you arm it before closing your door it can go off (if you slam the door closed).