The ultimate answer comes in saying that they are practically the same thing, and ONCE AGAIN the fighter makes the art, the art only modifies the fighter. We can argue all day without providing factual evidence about which art on the ground is going to be better, and we can say the BJJ will always win over Judo because that's what you guys think, but fact of the matter is, there are BJJ grapplers that can beat some of the best Judo guys in the world...
And there are recorded stories of Judo guys defeating some of the best BJJ practicioners in the world. Depending on which schools you work with, you will get different results. Depending on your physiology and preferences, you will train and learn different than anyone else.
There will be counter-arguments by those in the BJJ community, but Kimura DID defeat Helio(broke his arm because Helio would not tap, saying he was fine until his arm was broken in two places and he had to be hospitalized...), Yoshida has defeated Royce(Royce saying he was fine... Yoshida was concerned about the lack of resistance and called the Ref, Royce later said he was 'Resting', and chose to stop resisting during a choke.
http://www.judoinfo.com/images/video/GracieYoshida.wmv ) , Yasuichi Ono choked out Helio's brother, Jorge.
As I said, BJJ has also defeated Judo, but in general I prefer Judo, as stated above it is a much more 'diverse' art with more that is practiced than strictly ground techniques. The general demeanor of high level practicioners from each art is something I respect more from Judo than from BJJ artists as well.
Yoshida Interview Re. Royce Gracie:
http://www.pridefc.com/interviews/yoshida_10/yoshida_dec.htm
Royce interview Re. Yoshida:
http://www.pridefc.com/daily/2003/12/1001.htm