The part that's always fascinated me is- they had bigger brains.
Do a search on the Allegewi/Tallegewi peoples of America. Some of them were giants with huge heads. (...and presumably larger brains. Were they the Fomorian giants of Irish legend?)
Adena Skulls found in Ohio. These large headed people were reputed to have had two rows of teeth.(hyperdontia). They were wiped out by the invading American Indians from the west. These skulls are in the Ohio State Archaeological Museum in Columbus, Ohio. (females were 170 cm and males were 180.7 cm tall)
But of a different shape and constitution.
Remember the sloping forehead? Our cerebrums are much larger -- an advantage in reasoning capacity.
The Neanderthal brain was said to be more developed than ours with respect to nerve functions, leading to a probable advantage in instinctual responses.
When they are born, our children have much to learn. Neanderthal children may have inherited most of their "knowledge".