You can find more detailed answers elsewhere in these forums but here's the difference in a big nutshell:
Four to Six PS3 Eye Cameras
Higher framerate for more accurate captures
Larger capture space for bigger motions (20 x 20 ft)
Least susceptible to occlusion issues
Setup and calibration is more complicated than with twin Kinect
Some special clothing (color+style) and lighting considerations
Twin Kinect
Easy to set up and use
Can be used in a smaller environment
Capture space is small (7 x 7 ft)
Susceptible to some occlusion issues
Minor clothing and environment considerations
Single Kinect
Easiest configuration - no calibration required
Can capture using almost any computer
Most susceptible to occlusion issues
If you have Basic or Standard you can use either Kinect or PS3 Eye with the same license/software. Express works with a single Kinect only.
Twin Kinect can be used in two modes: 90 and 180 degrees. I prefer 90 degrees--in my experience accuracy seems better and occlusion has not beena major issue. This may depend on the motion you're trying to capture. I use twin Kinect for most of my mocap.
PS3 Eye produces the best results. I use this configuration for special situations because it is more involved to set up and use than Kinect.
All configurations use the same tracking system which is fairly easy to use with a little practice. When tracking, a modern graphics card, like Nvidia Geforce GTX 460 or higher is highly recommended. You may need extra cables to use any of the configurations--USB Active (aka, 'Repeater') cables is also highly recommended.
iPi Recorder and iPi Studio can be installed on different computers. For example, it is possible to record offsite using a laptop, then go back to your studio and track the motion using a desktop with a good graphics card.
Hope this helps.
G.
