Depends.
First time use, people stick to tren a because if you dont like the sides or the compound itself you can come off quick and have it out in a few days, where as with tren e you will have to wait 3-4 times longer.
Also the e ester has a compounding effect and the dose will continually build up in the body for a while until they reach the peak level where the half life stops the hormone from reaching a higher level (unless you introduce a higher amount of gear). This happens in the ace ester as well but at a much lower level and much faster time. Essentially you can build up more of the hormone with the longer ester in the body and have it in your body longer, where as the shorter esters build up quick and get out quick.