It depends on your use case. In the world of preservation, ZFS is a godsend. If you're trying to run a database, copy-on-write is going to defeat you. Not that it isn't possible, but it's surely something you're going to have to work against.

Fortunately, there are types of vdevs other than RAIDZ, and using SSDs for the ZIL can improve things as well.

http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuni...