Can I just say I *hate* how we in the West decided to categorize the Dragon Ball story arcs. A Saga, by definition, is not a small part of a larger story, which is how Dragon Ball Z classifies them as. A saga is the larger story. It's pointless syntax, I understand, by what other circumstance would you consider a large portion of a story a "group". It's dumb.
Anyway, the whole Future Trunks Saga as I'll choose to define it, since it clearly refers to the entire duration of Future Trunks time in DBZ which was definitely a saga, is easily my favorite. I'd say it's the peak of the series when it comes to character development, in large part due to getting the pay-off to Gohan's development, but it's worth noting Vegeta gets some of his strongest development here with Trunks (who himself has a solid arc). I also found the plot to be more engaging, if just because the actual antagonists are constantly changing. Was it 20 & 19, Nope! 17 & 18 are the real threats, and what's this, wrong again Trunks now we got a mysterious 16. But wait, now actually there's this really creepy horror bug thing named Cell. It's much more interesting then, Raditz going "there's two more coming this way" and then they came this way now fight. And I love how Cell's transformations relied on adsorbing the other two, since that creates different stakes and is more interesting than Frieza just having a bunch of transformations he didn't feel like using at the time. Which worked well dramatically for the fight, it just isn't engaging in a plot sense. Tien's moment of stalling Cell is one of the coolest things in the series, 16's death is one of the most effective emotional moment, 17 vs. Piccolo is my favorite fight in the series, and no fight in Dragon Ball will ever top the father-son Kamehameha climax. Honestly, think it has the best collection of fights too, 17 vs. Piccolo, Gohan vs. Cell, Goku vs. Cell are all top tier stuff. I always found the 19 battles fun, for seeing Goku on the ropes then Vegeta just clowning the poor Android (almost feel sorry for him running for his life).
Can't speak much to Dragon Ball since I saw it sporadically, Super which I've only see the movie recaps, or GT which I hated and couldn't get through the Baby stuff, but when it comes to Z, I will die on the hill that this was the best part of the series. Which in a way is a shame, since I actually think the Buu arc starts really promising (I actually thought it was going to become my favorite for awhile), but after all's said and done, it's probably my least favorite.