Well obviously we have the island level feat performed by a group of Seadramon in the earlier episodes of the show,
Largely after there really isn't much in the way of feats although several Digimon who appear have profile statements indicating high stats, such as Shoutmon X4S possessing a weapon which could save the world or destroy it depending on who wields it, Gravimon being able to partially destroy a star with an he can "survive but takes years to regenerate from", Tactimon's own star cutting sword, I believe another Digimon was stated to be able to destroy a planet etc.
The obvious issue with those being that we don't see any of that in the show (Tactimon never even drew his sword in the anime). Of course we have Apollomon Whispered's creation of an infinite sized dimension (ie a universal feat at minimum) which could lend credence to some of these statements.
Effectively if we are going PURELY by the feats we actually see from the death Generals (sans Apollomon Whispered) and weaker Digimon, then the Dark Masters win. If we include profile statements then the Death Generals win.