ZoL uses an emulation layer to make Linux look more like something with Unix ancestry, ancestry that BSD and Solaris share. The biggest difference I believe is

ZoL uses an emulation layer to make Linux look more like something with Unix ancestry, ancestry that BSD and Solaris share. The biggest difference I believe is in memory management / fs cache integration. In practice this means that ZoL may require more memory to be stable, or may be less stable depending on configuration if low in memory. I've run ZFS on Solaris (by way of Nexenta) and Linux since 2008 or so. I haven't seen much reliability difference in practice. I've had fewer hiccups streaming video from Linux though.