To those thinking about jumping onto the option of updating to macOS 15 Sequoia:

1) The developers for the macOS stateful firewall apparently forgot that UDP is a thing. As such, depending on your firewall config, silly things like DNS may stop working for some apps.
https://infosec.exchange/@wdormann/113153424126876349

2) The new XCode command-line tools breaks the ability for a number of MacPorts packages to be able to be compiled, due to not finding C++ headers.
https://trac.macports.org/ticket/70750

If these two things don't affect you, go ahead. Otherwise, maybe wait until the dust settles.