I liked Digimon more for watching, until Data Squad, then it was just over for me. While very similar to Pokemon in terms of "kids befriend and use monsters to fight", it is different in terms of direction of story. We got a chance to see our characters grow and develop as people. The struggles they faced trumps what the people in Pokemon go through and it taught more than it ever did.
But for playing, Pokemon puts Digimon six feet under. I've played very few Digimon games when I was younger, but I remember them as not being fun. Like the Digimon World games, all of them sucked to me and I stopped playing anymore Digimon after World 4. They were dull and lonesome, Pokemon was lively and had all my friends trading and sharing stories about how they got Mewtwo, tricked some kid to trading a Bulbasuar card for a Moltres, or discovered Missingno.