The PlaySport is Kodak's 'upgrade' to the very successful Zi8 model.Kodak Zi8 HD Pocket Video Camera - Black
There are some differences between the two units, so decide carefully what you will be making videos of before making your purchase.
The PlaySport is missing the macro function on the lense that can be found on the Zi8, basically, this allowed you to focus clearly on close up objects. Also missing is the 3.5mm stereo mic input. This was very usful if you were micing up an instrument and recording interviews. It also meant that you could stand as far away from the camera as your microphone cable would allow.
However, the PlaySport has some improvements and features that trump the Zi8.
In my opinion the video quality is better, capturing video in low light situations is improved, the brightness of the lcd screen is adjustable, it works underwater, its smaller and fits better in your hand than the Zi8.
The Playsports lense is wider than the Zi8's, meaning you can fit more in the frame.
To sum things up. If you are looking to do video blogging, music recordings, interviews and anything a bit more professional, then buy the Kodak Zi8. If you're looking for something a little more rugged, a camera you'd not think twice about letting the kids use, a video camera to take on holiday or just something to carry around with you to whip out when you spot something worth recording, then the PlaySport should be your weapon of choice.