1) Aromasin : ideal for cruising, easy on lipids, efficient. But on the other hand more expensive, harder to find.
2) Letrozole : i have to run it while on high test (about 600mg) or I get gyno. For the record i am EXTREMLY sensitive to aromatisation and need A LOT of AI when im running test. I used 2,5mg ED when runing around 800mg to 1000mg a test a week. Currently cuttin im using 1 tab ED for about 700mg of test E. Side wise it tends to lower your libido, even if your estrogen is in range.
3)Arimidex : To me a weaker version of letro, but doesnt impact libido at all. I would use it if i dont have access to Aromasin and running a low moderate test dose.
To me a good dose is simply just enough to not get gyno symptoms. And it happens to be a lot for me.