DBZ is fun to go back to, at least the Raditz, Saiyan, and Frieza sagas. The Cell and Buu sagas, on the other hand, tried too hard and were a complete bore.
I haven't watched a lot of Dragon Ball, but from what I remember, after the Freiza saga, they basically became gods and the show became boring, since they would always win due to their power (and if they died they could always just find the Dragon Balls and wish the character back).