> Does anybody actually use it? How are the experiences?

I tried really hard to once.  I got the FS into the kernel, put an LFS
on an MO platter, got it to mount, the cleaner daemon was running,
writes to the filesystem failed, didn't have time (needed to rebuild
X, I was hoping that LFS would speed up the build) to mess with it
went back to FFS.

I think I was running NetBSD/i386 1.0A March 4 1995.  I don't remember
the error, I could try again if someone wants to know since I have a
free platter side.

One of the things that I never figured out was "is there a fsck for
LFS?  do you need one?" /sbin/fsck didn't grok the LFS platter.