I don't notice much rattle now, but
My hardtop is on so it's hard to say. The only issue I've had with the carrier so far is that plastic rub block snapped in half. I got a new one sent under warranty no problem. A buddy of mine also made me one out of nylon and I'm having no issue with that. I've run 30 miles of trails around big rapids and seasonal roads around Harrison with that bumper/carrier without problem. I had it rhino lined fresh out of the box, that will take care of any rust issues. As for the open design, flush it with the garden hose when you wash it. I was actually very suprised at how heavy this thing is, the bumper itself should take some abuse, the jury is still out on the carrier. I am planning to mount my hi-lift to the lower horizontal bar and possibly fab up a cargo rack to sit above the spare. If that doesn't cause the pivot point to fail I don't think anything will. If it does fail I'll probably replace it with a truck spindle and hub.
I'm not sure about the quality of warn's stuff. IMO most of the smittybilt bashing comes from the fact that they are produced overseas.
I have their bumpers front and rear as well as their winch and have had zero problems.