Femara and Aromasin I have used both.
I didn't have gyno symptoms but they both work very well for reducing estrogen and creating a drier, less bloated physique. Of course the reduction in estrogen would reduce gyno you'd think.
Btw, unless on steroids you could probably get away with half a tab of both - they are very strong. I know one so called natural bb'er who used them for a show and promptly won as he looked so much leaner after taking aromasin. That means it reduces estrogen a LOT as the studies on it suggest.