SmartOS is definitely not intended to be used as a desktop system, but it can work great as a home server if you have some spare hardware.
OpenIndiana is another Illumos distro that can be used as a desktop. You get all of the core benefits of Illumos (zones, zfs, dtrace). The big downside is that you don't get the nice tools for managing zones/vms that SmartOS provides (vmadm/imgadm).
FreeBSD has ported a lot of the best features from Illumos so it could also work for you.
Just remember that an OS is only worth running if it has DTrace.
OpenIndiana is another Illumos distro that can be used as a desktop. You get all of the core benefits of Illumos (zones, zfs, dtrace). The big downside is that you don't get the nice tools for managing zones/vms that SmartOS provides (vmadm/imgadm).
FreeBSD has ported a lot of the best features from Illumos so it could also work for you.
Just remember that an OS is only worth running if it has DTrace.