your going to get a close vote between KOR, IRO and JKS sliders. all three will be highly regarded. one thing to keep in mind is the shipping cost for them to get to you. something im guessing most people dont consider, because the most important questions are what you asked. face it that's what really matters. protection, durability, clearance, warranty (if any) are the main points of concern. all three of these brands, guys here are running and in their build threads and they praise the design and ruggedness of all three.
but dont discount when it comes down to how much will it cost to ship 40-60lbs of steel to me as part of your consideration. you cant go wrong with any three of them, but save some coin for another item on "the jeep list"
2012 JKU Rubicon - all stock at this point
2002 WJ - 4.7L V8 - Selectrac - D30/44 - 255 BFG AT's - BB - Rancho 9000's
1999 WJ - 4.0L I6 - 4x4