The answer to this question is completely subjective. The one with the least amount of personal negative sides is the better. Some folks respond differently to each of these AI's. what they do for me might not be the same for u. Adex is a more dependent on protocol and Aromasin is more dependent on dosage. Adex is harsher on lipids and Aromasin is less. Does that mean its better? Not in the least. If u don't respond to aro why use it? If u don't respond to adex why use it?
To know which is better honestly u must first do large amounts of research if u have used neither. Weigh the pros n cons of each. Make ur choice and follow through with a consistent dosing protocol. Keep a log and run some labs. If u get bad sides or do not respond well switch them up. Try the other and do the same. Keep a log and run labs. Find ur happy dose for either and make the determination based on personal experience and correlate that with lab results. Only after doing that can u make the call of which AI is best suited for u.
For a person to say which is better I'd say to them that its not always going to be the same for the next guy.
Now for PCT that's easy. Aromasin and its ability to permanently attach itself to the aromatase enzyme and its igf benefit and its endogenous test benefit makes it the obvious choice. Unless of course u and Aromasin don't mesh well physically.
Just wanted to throw this perspective out there.