Four PS3 Eye cameras is a good system but it will require more room than dual Kinect. This system is generally better if you need more room to perform in and have the space available. It is also more complicated to set up than Kinect.
If space is limited, you should not bother with a 180 setup for dual Kinect Sensors. Even set between 60 to 90 degrees, the dual Kinect setup can resolve many occlusion issues. For example, in the 'chainsaw dance' sequence of my short film
'Happy Box', the character makes a 360 degree turn (several times in the original captured data,) and iPi Studio tracked this motion perfectly. The Kinect Sensors for this session were set to less than 60 degrees apart. (I can check my calibration scene for actual measurement if you're interested, but FWIW, if you look at the demo video on my
YouTube test channel it looks like it's barely 45 degrees.)
Hope this helps.
G.