Poor enemies for the most part, with the exception of Baby (Bebi) Vegeta depending on region & Omega Shenron, the first few sagas were awful. Reverting Goku back to a child was just silly and the whole show felt a lot more childish and aimed at children. Good sagas were too short, i mean Super 17 saga was 7 episodes long. He was claimed to be (after cell was also claimed to be) the ultimate android yet his saga lasted 7 episodes. Had so much more potential for that character. Yet the awful Black Star Saga was 16 episodes long and boring as hell.
They also ruined Vegetas character yet again & Trunks too and totally ruined how powerful Super Saiyan 3 was meant to be with a new stage that looked like it was a concept thought of by an 8 year old child in a fan fiction.
The Buu saga was a good place to leave DBZ and the ending of DBZ could have been continued after Goku flies off to train with Uub after Uub matches Goku in a battle. Saying he will return one day for one more battle with Vegeta.