I've made extensive use of the Vision Pro webcams. Today I compared the image to the built-in webcam on my MacBook and I was so impressed by the superiority of the Vision Pro I wrote one an rare "rave" review for Amazon. It's my first five star review in years ...
Amazon.com: Logitech QuickCam Vision Pro for Mac (Black): Electronics
I've purchased seven of these cameras, 5 for a team at work, 1 use at home, and 1 for my mother's Mac Mini.
Most of the cameras are on XP machines. As mentioned elsewhere these cameras install without device drivers on XP SP2 or later. Unlike the superficially similar but less expensive QuickCam Pro 9000 they do light balance and focus through camera hardware. That means we don't have to deal with flaky device drivers (rarely done well for OS X), and there's less demand on the CPU to manage the device....
... I've compared the video quality of this camera to the pinhole webcam that comes standard on modern Macs. It's light years better. There's really no comparison. It's better in low light, it's better at focus, it's higher resolution, there's far less image noise, etc.
The built-in microphone is superb. We get better sound quality using Google Video Chat and this device than we get with high end conference phones.
I'm a hard consumer to please, but I am very pleased with this camera.