It used to be feasible to get on DK on pokemon stadium in certain transformations or Yoshi's Island.Certainly it's among the best Dtilts but cases can definitely be made for MK and Swordfighter having better ones. MK's is frame 3, starts actual combos, jab locks, and even trips at a 25% chance. Swordie's is frame 5 and does 8% with Melee Marth/Roy total frames (19) combined with mostly vertical knockback.
Speaking of trips. Frame data question. Marth's Dtilt is supposed to have a 35% trip chance but I don't remember ever tripping someone with it. Why doesn't it trip? Is it the 30 degree kb angle that makes tripping impossible?
It's the issue of the angle/high base.
And while those two are better combo dtilts, Marth's is... a walling/poking down tilt of utmost quality.
Swordfighter's is a good shield poke though.