The aromatase inhibitors (arimidex, femara, aromasin) are better to use DURING a Testosterone (or other aromatizing AAS) than either Clomid or Nolvadex. I have found, though, if your BF% is lower than 10%, that Nolvadex will be sufficient to block estorgen effects. Of course, there are those that are just genetically prone to gyno and require an aromatase inhibitor DURING the cycle.
Nolvadex with HCG for PCT is better, for not only does Nolvadex block estrogen but it also stimualtes LH release. None of the aromatas inhibitors stimulate LH release. Remember, you do need some estrogen for recovery.