The main difference between different esters is simply the number of carbon atoms in the ester. Propionate has three carbons, acetate has two, isobutyrate has four, enanthate has seven, cypionate has eight, and decanoate has ten. More unusual esters, such as cyclohexylmethylcarbonate (used in Parabolan) has eight carbons and one more oxygen than the above esters making it the heaviest.
Therefore, the esters of trenbolone in order of potency when compared miligram to miligram (from most potent to least):
1. Tren Acetate
2. Tren Enanthate
3. Tren Cyclohexylmethylcarbonate (Tren Hexahydrobenzylcarbonate)
The differences in potency caused by the esters are negligible. So, you should base your choice of Tren on how frequently you plan to inject, how much you trust your supplier, and how much you trust the brand of tren you purchase.