I've never used it so I can't really comment on how effective it is, but I believe it was designed as "dianabol lite".
I'm pretty certain it was created by the East Germans by altering the structure of dianabol slightly, especially for use with female athletes (although it was used by male athletes as well, because of the fact there was no test for it (because no one outside of East Germany knew it existed)) who found the androgenic side-effects of dianabol too harsh.
So I wouldn't expect gains to be better than dianabol on a mg-for-mg basis.