It does a good job. With a couple of patches, it will even preserve file flags and creation times to pass every backup bouncer metadata test.
Unfortunately it is slow compared to the old rsyncx. A job that took 1.5 hours with rsyncx takes about 6 hours with rsync 3 with extended attribute support turned on. But that time is for syncing a couple terabytes of data, so if you aren’t comparing that much data, the performance hit won’t be as dramatic.
For a backup that passes the backup bouncer tests, we’ll have to deal with the speed trade off. Plus rsync 3 is being actively updated and is already much more stable than any previous version of rsync for Mac OS X.