One thing I hate in FreeBSD - is the speed of maintainence operations.
To install (or upgrade) one port you have to wait half an hour...
To update system with custom kernel/userland parameters, you should wait several hours... Then you call mergemaster, which asks you a dozen questions about config files (and most of changes doesn't impact on the current system, but just in case there is something important, you have to review them).
Comparing to "do-release-upgrade" on ubuntu, the speed of operation is unberable. And binary updates just don't do everithing you need (e.g. dtrace world, necessary ports options...)