Factors for me are gyno, how much gear before you bloat up like a balloon, and how bad will my face bloat up (this is so noticeable on me ). For all these letrozole and anastrozole are both great choices. I have yet to use aromasin...
I would go with a combination of low doses of liquidex and nolvadex while on cycle and nolvadex and hcg for post cycle recovery. .5mg eod l-dex and 10mg eod nolvadex would be sufficient for a moderate cycle containing a few aromatizing substances.