anadrol is the more powerful compound, but they both have merit
however, the mechanism through which anadrol causes gynecomastia is not widely understood. while anadrol is not believed to be estrogenic in nature, it does, if I recall correctly, demonstrate an affinity for the estrogen receptor. as a result, the measures that must be taken to prevent gynecomastia while using anadrol remain a mystery... though you cannot go wrong with letrozole, as it does a great job of reducing E2 (around 55-60%).
dbol on the other hand, directly converts to estrogenic substance.. IIRC, it converts to a MORE estrogenic compound than estradiol itself. Letrozole would be very useful here as well (im a bit biased, as it is my favorite AI, but it IS the best available).
dbol is a great addition to any cycle, as is anadrol. however, the latter tends to leave users with rather undesirable side effects - such as loss of appetite, which, in my opinion, is reason enough to limit its use to precontest/dieting phases to preserve strength and size.