Dropping the tank isn't that bad, just kind of tedious and you need to make sure it is near empty and the pressure relieved. The Poly skid is expensive almost to the point of ridiculous, and a pain to install, but like the rest of the system it is completely bombproof. Good luck denting the thing. I could easily jack up my Jeep from that skid.
The Rock Hard is an easier install and a hell of a lot less expensive, and will do its job. If you're bringing down a fat 4-dr Jake on that skid regularly though, they will dent and deform a fair amount. Not like the stocker, of course, but you will mangle it some. Some guys are installing ribbing on the inside of the skid to keep it a bit stronger.
If you can afford it and don't mind the one-time install pain, I'd go with the Poly. Otherwise the RH will be fine.
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