Personally, I'd go with backup&restore. In addition to this, use the downtime to update the host's firmware (HP released a couple of critical fixes regarding the RAID Controller and some HDD models lately).
What I would do - to avoid any issues - is to remove the ESXi host from vCenter, replace the disks, update the firmware, re-install ESXi and as the final step add the host to vCenter again.
André