They are similar to what they do with lowering estrogen levels.. but there is a chance with estrogen rebound when you come off of arimidex. Aromasin is a suicide inhibitor, so there is not chance of the estrogen coming back once you come off.
If you don't have your AI already.. check out AG-Guys. They have the best research chems in the business.
Your cycle is also pretty mild. N2BM Liquidex would also be a great choice. It is the strongest OTC AI on the market. It is a suicide inhibitor like aromasin, and will help to keep estrogen in check with out lowering it too much, which can be bad. It is also has many other qualities that make it a great choice for on cycle and PCT.. you can read about it here:
Liquidex AI
You can't go wrong with either one. Just remember it is more important to prevent the problem, rather than try to cure it. Waiting to see if you need it is just asinine. Run your AI from the start, and adjust your dose depending on your needs.
Best of Luck.