ext4 because I value my data and don’t want to lose it. I used to mess about with ZFS for mass storage but it’s a university course to learn how to use and have decent performance.
I used to use XFS, but ext4 caught up.
And I used to use XFS… on something other than Linux.
Saved you a click: Their ploughman’s pickle. I didn’t even realise they made this. Why would anyone use anything other than Branston anyway?