How realistic are the veins?

I can't speak about that toy specifically, but the material it is made with, Futurotic, has gotten really bad reviews based on the fact that it is extremely porous (which means that dirt, oil, and bacteria will get trapped inside) and in some cases leaking a chemical residue.

In my opinion there are toys out there that are very realistic but made of much safer materials, such as silicone (#1 safest) or high quality elastomer (still somewhat porous but not as much, and no residue).