There isn't much of a discussion imo. The people who like it still like it, the people who don't won't. As for me, I've been meaning to try out Time Machine & ZFS so I just started up my OSx86 torrent.
A bland OS X install can't write to a ZFS partition yet. You could try prereleases of ZFS for Mac from http://zfs.macosforge.org if you want write support. However, it doesn't let you boot to a partition with ZFS or index the partition with Spotlight. There's a few other limitations as well - look around the trac wiki and you should find the list pretty easily.
