Aromasin is a better choice for PCT IMO it lowers estrogen, raises free test and IGF-1 levels. It does takes a little longer and has a shorter half life than Adex. Unlike Arimidex, Asin is a suicide inhibitor so there's
less rebound estrogen effect when stopping. Price is higher in the long run since the recommend dose is 25mg ED.
Arimidex levels rise quicker, around an hour, with a 40+ hour half-life. Adex doesn't inhibit aromatase it competes with it at the receptor level. Neither will "trash lipids" alone and the recommended dose 0.25-0.5mg EOD makes Adex infinitely cheaper to run. I prefer Adex for estrogen maintenance on cycle or in my case forever.
In simple terms, Asin for PCT since the rebound won't screw you up when you stop and the estrogen suppression is 70-90%.
Adex for TRT or on cycle since it works well with slightly less suppression of estrogen. I personally prefer to be a little "wetter" when bulking and Adex is orders of magnitude cheaper
References for those who want to get deeper:
Clin Endocrinol (Oxf). 2005 Feb;62(2):228-35.
Effect of aromatase inhibition on lipids and inflammatorymarkers of cardiovascular disease in elderly men with low testosterone levels.
Dougherty RH1, Rohrer JL, Hayden D, Rubin SD, Leder BZ.
Arterioscler Thromb Vasc Biol. 2002 Jul 1;22(7):1136-41.
Prospective study of effect of androgens on seruminflammatory markers in men.
Ng MK1, Liu PY, Williams AJ, Nakhla S, Ly LP, Handelsman DJ,Celermajer DS.