I’m using Xcode daily at work with Xcode 8 and Xcode 9. (this is on 6-core fast machine)
On my laptop I’m using Xcode 10 with a modern 2018 13" MBP.
Most of my work is with JUCE while I’m now doing some personal iOS app with Swift.
Overall, Xcode is mixed-bag for completion (sometimes everything works fast, sometimes slow) I don’t know what projects you’ve used but I didn’t see that much performance difference between JUCE based cpp project and a Swift project (workspace…) with Firebase pods.
Keep in mind that JUCE default projects are with many modules. so it is indeed has A LOT of headers.
Another thing I see is conflicts between Xcode versions, If you’re using Xcode 9 and 10, you’d might be better deleting the
sometimes it breaks for me if I switch to much between Xcodes.