Build time. If you only need one or two components (clang, clang-tools-extra) and trim down the number of target architectures, it's not so bad. But if you want most of the components and architectures enabled, and tested with a Release-with-asserts build...

The build parallelism scales pretty well though so if you want some white noise in the background, by all means. It's kind of nice for keeping your feet warm sometimes.

Dependencies are few and largely optional but build time is tedious