The black one I bought is weatherproof, for sure, I used it to cover holes on my car, no problems with water leaks since then. also the tape did never fall off like the other "normal" duct tapes. My car is very old, and I still think its better to invest in a new car than repairing it. Meanwhile, this tape is a solution (Note: I live in south America, Uruguay)
I think its more waterproof than standard duct tape. I heard way back of some people that were white water rafting used Gorilla Tape to repair their raft and made it back to camp safely. I wouldn't recommend using Gorilla Tape for anything extreme like this.
I think the black might have an edge on the white,for toughness but both are far superior to any other duct tape out there,neither are truly water or pressure-proof. Surfaces must be clean and dry B-4 applying,in a pinch it will work for,awhile,ROTS-OF-RUCK,it might be good enough to get you home,till you can make a permanent repair!!!