+1 on this

Got working SwiftUI previews on a 50-100k LOC project with many big libs as dependencies, must be hundreds of files but havent counted. SwiftUI code is gaining share of the total UI code, probably around 20-30% now

Mock data is a must.

Need to be mindful of the preview build (+ preview simulator startup) time too, sometimes it will timeout but just building again (now warmer) will make it work

Had some initial issues around processor arch (Intel vs M1/arm), think I’m still running XCode under rosetta otherwise it wouldnt work.