Yo Brett...thanks for the info...here is what I know about Arimidex...
It was developed to be a treatment for advanced breast cancer in women. It acts to block the enzyme aromatase, which then blocks the production of estrogen. Since many forms of breast cancer are stimulated by estrogen, the reduction of its production via Arimidex is thought to block the progression of the disease.
For BBers using steroids it appears Arimidex blocks estrogen better than either Nolvadex or Proviron ever could. By taking 1/2-1 tablet per day, one can effectively stop all estrogen related side effects...gyno, water retention, etc.
The only problem with Arimidex as I know it is that it is so good at halting the effects of estrogen that there can be a very negative affect on cholesterol levels...namely, the suppression of good, HDL, cholesterol production. Nolvadex does not seem to have this same negative affect.
Besides this, I only hear good thing about Arimidex, unless you want to factor in the cost...I know prices can be as high as $250 per 28 tabs...whew!