Tren hex is a poor ester, as it is bigger than either the Tren ac or Tren enth esters, so you get less Tren per gram, which is never good.
It was the ester used in the old Parabolan, and the 76mg amps, yeilded only 50mg of active tren, so that means more than 1/3 of the compound is ester weight.
I would go with Acetate or Enth every time.
Also their is the fact that the hex ester is a lot more expensive than either if the other 2.