it's all preference bro. aromasin is a suicidal inhibitor meaning it attaches to the aromatase enzyme and destroys it, rendering it useless. It is considered the weaker of the two though because t is difficult to rapidly bring down e2 levels with it. The good part is that you run a lower risk of crashing your e2 levels into the ground which makes you feel like death.
Adex binds to the aromatase enzyme and just occupies it so it cant use it's aromatising effects. Once the drug becomes inactive, the enzyme is free to aromatize again. This can sometimes lead to estro rebound. This is avoidable though if you know what you're doing. Adex is stronger than aromasin and is more effective at lowering e2.
give both a try and see what you like better.