Digimon isn't even close to being a good Pokemon knockoff. Just compare a few creatures and note the differences. While Digimon have to resort to spikes, robotic limbs, armor, masks, markings, and all this other crap, Pokemon is much more simple in that regard.
Another thing that sticks out about Digimon is the color schemes. The color scheme of a Digimon is almost always random, and without any reason. Pokemon, though, have meaningful color schemes, or at least ones that look good together. Although some of the newer Pokemon exhibit Digimon-like traits (Black and White Kyurem, anyone?), I doubt that Pokemon will ever get quite as bad as Digimon.
Anyway Digimon for me. Pokemon just isn't all that appealing for me anymore, and is always "same-y". I feel Digimon always got something entirely new.