I thought they were both rather shallow. But for some reason Pokémon had some more memorable stuff like Team Rocket being the most pathetic villains in the history of anything, always getting blasted off into the sky and finishing with a small audible sparkle.
Digimon didn't seem to be able to decide how edgy or serious it wanted to be, and the character design was all over the place. Pokémon had a very episodic structure, which meant the next episode could bring something completely fresh on the table. Didn't necessarily succeed in doing this, but generally you didn't know what was coming towards you, which is thanks to excessive filler between the gyms and negligence of the titular "gotta catch em all" mission.
Digimon was highly formulatic.
Find the X devices. Once everyone has one, everyone gets their first evolution. Once everyone has one, everyone gets their second evolution. We defeat a minor boss. Everyone upgrade to third evolution to slay the dragon. Time for the fourth evolution and/or Deus Ex Machina to slay the Big Bad that wants to conquer the world.
They both were nowhere near stellar tho and are mainly held up by nostalgia. I don't think either was clever or thought-provoking or pushed any limits. I think this episode would be better with a title like "Which is the best (nostalgic) mon series?" and even then you got somewhat competitors like Monster Ranger.
Anime in itself is way too diverse to make it a competition with clear overview and few contestants. That's like asking "What's the best book?" or "What's the best song?" without relying on stats like popularity.
