Well, for a start he outranges us in both the air AND the ground. His tilts outrange almost all of our attacks bar turnips essentially, and when fighting in the air, his Bair outranges all our aerials, and really he doesn't need much else in that sense. In other words, you frequently have to use turnips to get in close.
As well as range, DK has way more killing power. DSmash is pretty fast and kills us at like 70-80%, his neutral B donkey punch kills us at 70% when slightly less than fully charged, and Uair, Bair and the like are all powerful finishers as well. USmash and FSmash are powerful too, but they're easier to avoid.
Whilst he can kill us at 80% or so with ease, he lives **** near forever, since he's the second heaviest character in the game, and his up B can stop all momentum (in the same fashion as bucket braking) after using Bair. If he combines that with good DI, then good luck trying to kill him at anything below 150%.
Yes, Peach is definitely better at comboing at close range, but since DK lives so much longer than us and has so much more killing power, that advanatge doesn't mean so much. To summarise, IMO Donkey Kong > Peach because he hs more range, much more killing power and much more survivability.
*prepares to have argument totally decimated*
