Ask 10 guys and you'll get 10 different answers. Well really only 2. Some people claim that tren is tren and once the ester is cleaved it acts the exact same. Others tend to notice a huge difference in ace and E. I can only speak from anecdotal personal experience, but ace hits harder both good and bad for me. Never tried hex so can't comment on that.
Philosophical side bar, I think there is a lot of hubris when it comes to pharmacology related to gear. Guys THINK they know things for certain, like that the esters don't change chemicals' outcomes, but there's so much we still don't know about the human body, that nothing is really certain. I value anecdotal experiences more and more as I get older. Science is obviously great as far as it goes, but it doesn't go as far as we sometimes like to think it does.