I've been wearing contacts for 12 years, so I'm not too worried about contacts themselves. I'm mostly concerned about getting knock-offs made from inferior or possibly hazardous materials.
On most of the lenses, I kept seeing that they were made of "2Hema," and I can't for the life of me figure out what that is. Most of the lenses I've ever encountered are made of Ocufilcon or Galyfilcon silicone hydrogel. I keep wondering if that's just another name for a type of silicone hydrogel, one that they use in Asia.