Actually, I find it kind of hard to go back to DBZ after watching Kai, but I can still enjoy both shows equally. DBZ is a part of my childhood, but looking back on it after all these years, the filler kind of ruins the pacing of the series, especially during the timeframe when it finished it's run on CN, I picked up the manga and noticed how fast it was compared to the anime. I like Z and all, but even I admit that it has it's share of faults when it came to the anime adaptation.
Kai is basically following the Manga for the most part, but there are some odd edits here and there, sometime the art of the series feels like early Saban days where they corabined episodes, but I feel so happy to go through something that took less episodes than more. Hopefully the fight between Freeza and Goku this time might be a little bit more smoother.