Everything I have seen in this thread about Clomid and Nolvadex is consistent with all my research and experience.

Nolvadex blocks estrogen at the pituitary gland causing increased LH and FSH production the same way Clomid does.

However Nolvadex may have some estrogen blocking capabilities in the breast tissue as well as at the pituitary gland. This obviously explains why some guys feel improvements in Gyno related symptoms while on it.

As far as choosing between the SERMS goes, most endos (in the U.S. Anyway) prefer clomid over Nolvadex for increasing testosterone in Men. This is why my old Endo put me on clomid instead of the other SERMS.

As far as the dick shrinking goes, I experienced this on clomid as well. My Endo thought that perhaps the clomid "acts as" an estrogen inside of our bodies in many diff ways that can't completely be explained.

Note I did a two year clomid restart under supervision of my Endo.