I would say either way you go you wont be disappointed. Both are bomb proof, both mount very strong(they both transfer the load to the sub-frame assembly) and will give you years of enjoyment.
It basically, IMO, comes down to which do you like the looks of better. Metal Cloak has the various flair options as well that you can change as you go compared to Poison Spyder.
I personally went with Poison Spyder as I didnt like the way the Metal Cloak's looked on the JK. I think they look fantastic on TJ's, but I just couldnt come to like their look on the JK, again, personal preference based on looks, not function.