It's a retool of the Dragonball Z Funimation dub. The main thing here is the fact that they have cut like 80% of all the filler scenes (and even filler episodes to boot) out from the dubbing. And the transformation/power up scenes don't take more than a few seconds now.

For instance, the trip to Planet Namek for Gohan, Krillen, and Bulma took like 5-6 episodes in the original DBZ dub; in Kai, they depart from Earth the end of one episode and are at Namek at the start of the following one.

They've also improved up the quality and formatting of the pictures a bit, and made it capatiable with widescreen tvs. so it's a lot cleaner now. There's also less woosley-isms and bowdlerizing (though they still censored stuff like nudity and booze references).

Other than that, it's same old DBZ people grew up with.