The whole Toriyama's influence thing is a big deal for me. That aside, reasons I prefer Super so far:
Characters seem more lively. The Black Star Dragonballs and Baby sagas had some interesting characters, and even if I wish Uub was handled differently I enjoyed his character, but in Super, we have: Beerus/Whis, who add an element we didn't really have in GT, of godly figures who take an active interest in our protagonists; Trunks returned, and seemed to have some legitimate character development (Vegeta's character arc finished in the Boo saga, but it was great seeing him taking on a warmer role with Future Trunks, and I feel the interactions with his future counterpart had a lasting effect on Present Trunks); Zamasu/Black had a descent before our eyes unlike anything else in the series, tremendous development.
The world also feels much, much bigger. I'm not a huge fan of GT, but the Black Star Dragonballs and Baby sagas had a lot of good things, and I think it felt a lot like something that would happen in the Dragonball universe. It felt like a bit of a gaiden, aside from Piccolo's death and Buu being absorbed into Uub, but I liked how it played out. The Super 17 stuff isn't something that interested me, but I did like some aspects of the Shadow Dragons saga. Was important for there to be consequences for using the Dragonballs. Goku sacrificed himself, and atoned for using them. Like with the Black Star/Baby stuff though, it felt like something that while it was an apt concept, felt constrained to the canvas Toriyama painted through Buu.
In Super on the other hand, it follows a natural progression from the beginning of the original series. The scope increases: martial arts tournament -> saving the world from a native (or so we believed) threat, twice -> saving the world from an extraterrestrial threat, twice -> going to another planet to repair the damage, and in turn save the galaxy from an empire -> defeat a galactic threat from another timeline -> defeat a legitimate universal threat (over time). GT kind of stopped there (not just speaking of power scaling, though I believe SSJ4 Gogeta did have some impressive powers at the end). Super moves forward by expanding the hierarchy of gods, and just recently we had a multiverse/entire timeline destroyed. That's pretty crazy! Now, we're at TTGL levels of scale, so I'm not sure how one moves beyond there, but there is still a lot of room before Goku and Vegeta reach that point.
Super all in all has been pretty interesting so far, in terms of content, but it isn't a perfect production. There have been a few poorly animated episodes that have detracted from the plot/character development (most have been fixed in blu ray releases from my understanding, except for one particularly shoddily animate episode in the RoF saga), but the quality has generally been more consistent than in the original series. I do miss a lot of the original sound effects, their absence takes something away from the viewing (since the god level ki is a different type of power, different powering up sounds don't bug me as much). I prefer the manga, as it seemed to be an abridged version of Toriyama's scripts/outlines (while the anime seems to be, as per usual, an expansion), and wanted it to become a semimonthly release, but given how long Toyotaro has made the chapters, I'm content with the current release schedule. Still is a bit frustrating reconciling between the two what was Toriyama's original intent (what I'm going with now is, if something is present in both mediums, then it's something that Toriyama intended to do). While I enjoyed the characters in the Universe 6 saga, I always felt the tournaments were too formulaic, and once you've seen one, you've seen them all. In an adventure/fighting series I get that there are only limited opportunities to provide things with structure, but you can only go to that well so many times. Now, the assassin theme is something that would be an amazing addition to the series, and if the rumors of Hit returning are true, would be very welcomed. Especially if Hit is a hidden/stealthy assassin, and there is a constant threat of him appearing. Getting ahead of myself here, so I'll leave it at that, but there is a ton of potential.
Lastly, in addition to scope, I do enjoy a lot of the extra world-building. The new details (like the potara lasting for an hour on mortals, for instance) really flesh out the universe, and are a really fun twist. More flashbacks is always welcome, I liked seeing what we have of Trunks's timeline since we saw him defeat Cell. It's also nice seeing more of Kaioshin—the Buu saga didn't do him justice—and less of Goten (don't want to rant about him here, but I always felt he was a useless character, and would have preferred that he didn't exist, eliminating the Gotenks nonsense in the Buu Saga, and giving us more development of present Trunks before Gohan's return).
I think that's everything, apologies for the disorganized rant.