I have a player rig that uses 3 rigid bodies and two configurable joints. My rig had some real issues with beta 4, but beta 5 seems to a little better. I am trying to track down one last glitch, but it is very hard because the glitch does not always show up in editor mode while being prevalent in the build version. I think it has something to do with assigning the rotation on the transform. In the past that did not seem to be a problem, now it seems to affect the physics calculations, but to be honest I am not sure at this point. I am hoping someone with Unity can make a post with what was changed in regards to the configurable joints. So that I can focus my efforts a bit more on what is causing the glitch.