Karachi Sust is manufactured by Abbott Laboratories in Karachi, Pakistan. They produce it under License from Organon. It´s quite a fine brand of Sust, I can highly recommend it!
I have used the Nile, Mexican Redijects and Russian. I would rate them like this: Karachi, Nile and Redijects. I didn't like the redi's that much because they come with such a huge F'n needle and some of mine were not filled.