My personal experience: after working on existing UIKit application for over a month or so, I spent a couple of weeks trying SwiftUI out in last summer, by first watching most of the Stanford's great SwiftUI iOS lectures https://www.youtube.com/watch?v=SIYdYpPXil4&list=PLpGHT1n4-m...
With the little experience I got, I agree with mikenew's comment. SwiftUI felt like an expressive way to define UI elements, but I had some small weird details that took long time to solve, perhaps because I defined something in a way that wasn't supposed to. Ultimately, I mostly got the code to look in the way I preferred, but for example regarding animation or gestures there were some problematic details I didn't want to spend time to get exactly right.
Overall I enjoyed it much more than UIKit but I would hesitate to use it in the future in a professional setting without properly investigating how mature it is at that point of time.
If anyone is interested, here's the Shogi app I developed, intended for two local two players, and as a reminder I am quite new to the iOS ecosystem: https://github.com/EvidentSolutions/toodim
Thank you for pointing out the Stanford lectures. I wasn't aware of them and they look really good to get up to speed. I messed around with SwiftUI a while back but I haven't for the past year, so those should help me get back into it.
The game looks very impressive for being new to iOS. If you haven't looked into it yet, I recommend learning SpriteKit as well. Its animation system (SKAction) is pretty nice. I actually ended up basically re-implementing it in C# for another game I was working on, since it wasn't terribly hard to do (got the subset of actions I needed working in a couple of hours), and you can be very expressive with it, once you grok groups and sequences.
With the little experience I got, I agree with mikenew's comment. SwiftUI felt like an expressive way to define UI elements, but I had some small weird details that took long time to solve, perhaps because I defined something in a way that wasn't supposed to. Ultimately, I mostly got the code to look in the way I preferred, but for example regarding animation or gestures there were some problematic details I didn't want to spend time to get exactly right.
Overall I enjoyed it much more than UIKit but I would hesitate to use it in the future in a professional setting without properly investigating how mature it is at that point of time.
If anyone is interested, here's the Shogi app I developed, intended for two local two players, and as a reminder I am quite new to the iOS ecosystem: https://github.com/EvidentSolutions/toodim