Bible Jesus taught peace & goodness, then got mad and knocked over money-changers tables in temple---BoM Jesus got mad and wiped out whole cities & killed like a million people, then taught peace & goodness.
He might have actually existed. At least the political era of the New Testament was real, ie the Roman Empire's province of Palestine, Herod, Jewish society, etc. Much of the context was real.
The Book of Mormon Jesus is an entirely fictional side-story based roughly on the bible, in which Jesus, during the three days between his crucifixion and resurrection, visits not only "the spirits in prison" as in the bible, he visits ancient America too.
Side story of my own now...Mormons have grasped onto straws of what they see as evidence of a "white god" visiting the ancient Americas. Quetzalcoatl is probably the most overused one (http://en.wikipedia.org/wiki/Quetzalcoatl). But Q was definitely an Aztec/Mayan figure, so apologists have to translocate the legend to New York when they are in limited-geography mode. No such legend was known among the New England and Great Lakes tribes that I know of. Furthermore, Q's whiteness and beardedness was apparently groomed by Spanish conquistadors to make Q look like an oman of themselves, to favor Aztec acquiescence to Spanish rule. There's evidence that prior to Spanish contact Q wasn't white, wasn't bearded, and wasn't even human. The Q myth mormons buy was apparently rigged by the Spanish. Futhermore, this Spanish version of Q was old news by the time the Book of Mormon was published in 1830. Cortez conquered the Aztecs in 1519. Q was older news in Smith's time than Smith is in our time.
Amos, the BOM Jaheezus didn't visit the Nephites during his three days of "death", he visited them after his "resurrection". He was wearing his "body".
I'm embarrassed. A lapse in basic gospel knowledge. Yes, of course Jesus' visit was between His resurrection and ascension, not between his crucifixion and resurrection. That's an obvious mistake to mormons, and not inconsequential. The crowd touched him, in particular the wounds from his execution. And, the three days was spent preaching to the spirits in prison. Sorry.