I thought this may make for an interesting discussion.
I tried using BTRFS with snapshots. The thought of being able to roll back easily if something went wrong was appealing. I was using the snapshots for root and my home directory on vanilla Arch and Manjaro, but as @ricky89 said it got messy. A few times I was coming close to running out of disk space because of them.
So I decided good ole ext4 is good enough with a proper backup. However the default system on Fedora is BTRFS, but since there are no snapshots configured it works fine for me.
Back in the day, my favorite was reiserfs, which was considerably faster than ext3. In recent years I’ve been satisfied with ext4 or xfs, and when combined with lvm they offer the needed flexibility and good performance.
Lately I’ve been intrigued by ZFS and have been testing its features. Will also revisit BTRFS as time allows.
@J_J_Sloan if I’m not wrong reiserfs is Microsoft? It should be the Windows enterprise file system? I’m not sure we can use reiserfs on Linux?
My preference is using XFS, it’s very robust and is not getting fragmented after all. The only incovenient is I can’t make an XFS partition smaller, it support only increasing. A bit annoying but, nothing tremendous.
I’m not aware of reiserfs ever being ported to windows. It was the default file system of Suse Linux Enterprise back in the early 2000s.
After Hans Reiser was sent to prison for the murder of his wife, it fell out of favor, and its performance has since been matched by other Linux filesystems.