I haven't heard anything specific, so certainly take it with a grain of salt. I was considering using ZFS on my home backup server a while back but didn't want to deal with OpenSolaris, so I did some Googling to see if the BSD port was worth it. This was two or three years ago so I don't remember the specifics, but I decided it wasn't worth it and people griping about disappearing data, disappearing zpools, and stripes that acted like black holes.