This seems to me like very happy news indeed, but I'm interested in contrary opinions. There's a recent thread discussing how udev-197 breaks lvm2, but that's a trivial fix once you know about it.
The problem is caused because many apps including lvm2 install their udev config scripts in /usr/lib/udev/rules.d/ (where they never belonged in the first place IMO) and they should instead now go in /lib/udev/rules.d/. All you need to do is to re-emerge all of those packages *after* installing udev-197 and the config scripts will go in the correct place. You should do this before rebooting the machine because lvm2 won't work until its udev scripts are in the correct directory. Doesn't this seem to fix the problem with booting a separate /usr partition?
