Endless updates

In at least the case of Fedora rawhide you often get updates which is a little tiresome because there can be many many packages to update at the same time. If you choose to update, then update fails because usually due to some fake dependency on other package (especially if the package is backwards compatible). It also becomes tedious to even select which updates to apply or find the package(s) that are blocking your update.

But on the positive side, it does allow you to get the major changes to the core packages like KDE and Gnome without having to wait until the next release in a years time. Also with Fedora you can stop at a release if you get a system you like!