according to research sites i've read sustanon and E have almost the same sides.
the big diff between them though is sustanon has an ester that you will feel quick which is why i like sustanon. i dont want to wait to feel the effects hence i choose sust as my test.
but like said above over the course of time it really balances out. i guess its just a matter of sustanon has worked well for me so i will continue to go back to it.