I've not shot enough of either to be an authority, but someone who IS an authority in my book has told me that Goex is at the bottom of the heap quality wise in the BP world.
Now, that doens't mean it's junk... but I'm told the Elephant is great stuff for an "everyday" type BP, whereas the Goex is somewhat dirty and less energetic than the Elephant.
Best of the best is supposed to be the Swiss stuff, I'm told. Mostly I stick to 777 in my C&B pistol.