I'm not sure why repositioning the object would be better than destroying it and spawning it at the right player, but it seems to be only one object we are talking about, so I guess it doesn't make much impact on performance in what way you do it..
I would personally choose disabling the physics behaviour on the object when not needed and reenabling it when the physics are needed again, but like I said, performance wise the difference would probably not be noticable, so I guess it's a case of whatever you like best..
You could ofcourse check the difference in performance using the debugger to make sure..