dex is not particularly effective for drugs that tend to be subject to peripheral aromatization, methandrostanolone in particular. often a full 2mg daily of dex will still not stop dbol bloat and cramping.
aromasin on the other hand is very effective peripherally, highly suppressing what is generally E2 conversion.
arimidex is best at E1 suppression (tissue affinity, gonadal, adrenal, etc and because its a competitive inhibitor). it suppress e1 at even the lowest of doses, but takes rather high doses to see significant impact on peripheral aromatase (which if you have "issues" is generally where it is).
general reccomendation is aromasin as a base for most aromatic cycles with letrozole on hand. Generally also reccomend a dopaminergic, at least on hand, cabaser tablets or pramipexole (liquid or tabs). prolactin is as involved in gynecomastia and testosterone suppression as estrogen.