I use ZFSBootMenu to boot a single distribution on each of my systems. While it certainly can help booting multiple different environments, the real value-add t

I use ZFSBootMenu to boot a single distribution on each of my systems. While it certainly can help booting multiple different environments, the real value-add to me is that my entire OS is contained on a single filesystem. There's no longer a need to make an entirely separate boot pool to work around GRUBs extremely limited ZFS support. Because ZBM (can) use the kernel and ZFS userland+modules on your own system, it's never really behind what your OS is running. Additionally, since we import the pool read-only by default, new breaking features/pool flags in ZFS typically aren't a problem. It's only when you try to import a pool read-write that ZFS will have issues, so we detect that, warn you and then prevent it from happening. Since it also ships as an EFI executable that can import/boot any pool, it's really easy to make recovery media. Just throw the EFI on a USB drive with an ESP and name it BOOTX64.EFI and most modern firmware will use it in the absence of any other working boot entries.