Using ZFS over encrypted partitions, and the bottleneck is the encryption, not ZFS per se. And that because I'm running them on old CPUs without aesni support. Even on FreeBSD 11-STABLE amd64 boxes with only 4 GB RAM, which run just fine as desktop machines. So ZFS is actually a viable alternative. I was running UFS for a very long time, and wary of switching to ZFS for day-to-day uses, but I went to an all-ZFS-setup with the switch to FreeBSD 11 even on oldish hardware, and I'm not looking back. It's all too convenient to give up the upsides.