My experience in Mojave ~ no issues (so far). My development tools and environment include Xcode 10 and Homebrew formulae among others.
Xcode is miraculously running on my late 2008 MBP in Mojave and I'm able to deploy to my iPhone XS!
The only issue I've seen thus far is the iPhone XS Max simulator does not seem to work, however I suspect this is either a general issue or due to limited RAM/GPU/old hardware (I've only got 8GB RAM).