youre close, but:
- pride does not allow spiking
- ufc doesnt allow kicks, knees or stomps
to the head on the ground, the body is fine
- pride doesnt allow certain knees to the top of the head on the ground (ask igor

) ... though they seem to change this rule from fight to fight
the biggest difference is the issuance of yellow cards in pride, which force the fighters to put on a more exciting fight or lose 10% of their payday! they are issued for holding too much on the ground, holding the ropes, inactivity, repeated fouling etc...
in the ufc the fights progress more naturally(occasionally they stand them up but they dont take away their money) and are far more likely to be boring "lay and prays" (where a wreslter humps someone for 15 minutes) whereas in pride this would result in a yellowcard
basicallly, in japan they are concerned with putting forth the most exciting fights with the toughest(and by that i mean actual toughness or "bushido" during a fight; heart) fighters, and how you win is more important than winning itself .... wheres in the us its just about winning, and fairness
japan also has no drug policy (not that the ufc guys arent taking the exact same shti, but it speaks to the emphasis on putting forward the best product possible instead of having the most "fair")