The UI, from what I've seen, seems a lot less... complex?
I kind of like the more "sci-fi" look of things, but... Idk, it seems more like driving the Cyclops from Subnautica than it is like flying a spacecraft.
Then again, I can't imagine what kind of stress the devs must be under, having to craft something new, have it be faithful to KSP, but also have it appeal to the community.
In any case, yeah, I don't like the new UI that much.
Edit: Wait, no, I take that back, I actually really like how the staging and time "zoom" looks. I just dislike the navball as it stands now.