Thanks for the quick reply.
My reason to switch from FreeNAS to Rockstor is a bit petty, lol. Basically, I converted an old computer into a FreeNAS machine about 1.5 years ago knowing almost nothing about NAS’s, and was using Arch with ext4 on my desktop at the time. I set up some scripts to rsync my important stuff from my home directory to the NAS, and that worked well. A couple months later, I learned about btrfs and switched to using Arch with btrfs on my desktop. After several months of using the rsync scripts on btrfs, I looked more into btrfs send/receive and thought that would be a nicer solution since it’d be faster and wouldn’t have the issue of the me being able to change files mid-sync. But FreeNAS is zfs, so I decided to switch my desktop to zfs instead, and use zfs send/receive. After I eventually got Arch with zfs on root installed, everything was working well. Except I really just can not stand having to update the Linux kernel separately from the rest of the stuff, waiting days until the zfs stuff gets put out there. It just really bugs me for some reason. I also feel more comfortable with btrfs (probably because I spent more time with it), and feel 100% sure I can salvage a bricked btrfs setup without help while I would probably have to Google a couple things with zfs. So, I figured I’d switch my NAS over to an OS that uses btrfs and switch my desktop back over to btrfs, as well.
So basically, I wasn’t satisfied with a perfectly functioning rsync backup solution, decided to switch to zfs for send/receive functionality, but wasn’t satisfied with the problems that come from zfs not being officially supported by Linux.
And I think I’ve got my bases covered for making the switch to Rockstor. I’ve moved any data that’s being stored solely on the NAS to my desktop (the important stuff, at least - I’m going to be purging a bunch of junk thanks to this move), so I’ll just install Rockstor on the NAS, wipe the two data drives that will be a RAID 1 mirror setup, move the stuff back onto the NAS, do an rsync backup of my desktop’s home directory to my NAS, do a fresh install of Arch with btrfs on my desktop, then rsync my home directory back to my desktop.