The main story is all the same but you miss so much about the characters and so on. Then the story is all flat - just endless fighting without any sense. One of my favourite arcs - adult Gohan and young Trunks/Goten, but there is nothing about that. So sad.
I've started watching DBK just because the amount of DBZ episodes is too much, to rewatch it again, but it was a mistake so don't make it too. Because in that case you will lose a lot of joy or much of your time watching DBZ after DBK.
