Even after 8 years of using OMV the answer is not clear for me. Recently I have acquired a set of new drives as I outgrew my current storage, so essentially I am starting from zero. I have set up TrueNAS Scale with 2 striped RAIDZ1 vdevs, but not really liking TrueNAS for the limitations it brings essentially just for a (much) better ZFS support via the frontend I am thinking where to move further, considering the following options
1) ZFS, while works in OMV, its not supported out of the box and the plugin offers just the bare minimum of options, so when replacing a drive, scheduling scrubs and snapshots and restoring data from them basically I have to google the zfs commands and do it from the command line.
2) MegerFS with Snapraid is what I was using during the past years, and while it works well, this is also implemented via external solutions. Also I am quite happy I haven't had to restore any data via Snapraid, I am not sure what my success rate would be (and also it has to be done via the command line with no GUI support)
3) Btrfs seems to be supported the best (some of us remember at one point it was supposed to be the only filesystem supported by OMV) with automated regular scrubs, snapshots, etc., however it seems to me this file system essentially dead for storage arrays and superseded by ZFS (despite being a quite a fan of it and having all my current disk under OMV formatted to btrfs - however i still think its a great file system for the OS). Btrfs still does not have a stable RAID5 implementation, so i don't see how to implement something similar to my current striped RAIDZ1 config.
At this moment I am leaning towards importing my TrueNAS pool to OMV, schedule scrubs via a cronjob and give up on automated snapshots (as I would need to create multiple cronjobs for scheduling then destroying snapshots and I would likely mess that up). Otherwise there is nothing really in TrueNAS feature set that I could not do with the help of a few docker apps I am running anyway.