Dragon Ball Kai is worth the while but I don't find it nearly as good as the older version Dragon Ball Z.
A lot of stuff are cut out from Z in Kai. Which in some ways is pleasant. No Goku taking too long on snake way, no fake namek, no Garlic Jr. saga, no driving episode, and a bunch of other stuff. However, not without some downsides. I don't like how in certain scenes when something is cut out, scenes are jointed together but they don't make any sense. Like things are happening too fast or something doesn't really seem to connect. Then, there were good stuff from Z that were taken out.
The animation in Kai looks upgraded. Sometimes I don't see what the difference between the two versions are though. Kai got better most of the time with the animation. Except, there are times when the animation would look tremendous in one shot but then another shot later the animation gets back to being average. Like it doesn't feel whole.
Voice actors sound different than in the older version. Some from the older version are deceased. While others are still around. Those who are still around have showed their age in their performance in their voice acting. Take one for instance, the Seiyuu for Cell. His performance for Cell in Kai sounds weird to when he did Cell in Z. But many of the actors are still good as they were in the older one.
Music in Z was better. Background music in Kai gets boring. The music for Z was more exciting to listen to than in Kai.
Something I just find strange. Why is Lunch shown in the credits for the first ending song for Kai if she didn't make an appearance on the actual show? Makes no sense.
I like Z a lot better than Kai. With Z you have the whole thing which I prefer. Kai has faster pacing and people who aren't fans of the series will like Kai better.
These are the things I have for now.