I don't believe Digimon is a rip off of Pokemon at all. Talking show wise, Season 1 and 2 were more of 'kids have pet digimon...digimon evolve and kick bad buy butt' I suppose you could sort of relate this to pokemon, but the big difference is that Digimon actually interact with things a lot more than Pokemon, and they're not caught and stuffed into little balls.
But when you get to Season 3, Digimon Frontier, you see a big change. No longer do the kids get Digimon friends to help save the DigiWorld, they find the Legendary Digi Spirits and evolve with them, to form human/digimon forms, etc. As for Season 4, Digimon Tamers, it sort of goes back to what 1 and 2 was, the 'Tamers' have Digimon companions, that use their Digivices to use attacks. I dont know anything of the new Digimon season, so I can't really comment on that.
Just to say that Digimon is a rip off of Pokemon is kind of harsh, you should really look into the series before planting a bold statement like that across it. From a far look, you might think that it's the same old Pokemon ploy, catch a monster, use them to fight..but really they befriend Digital monsters, and use them to fight (and Digimon do say more than just their names) In the end, both series are really entertaining, it's just that Pokemon survived better over here and the games are more successful, I even dont enjoy Digimon games, just the show itself.
