It's amazing to see users still debating about "foofs ate my files, so I switched to barfs".
FWIW, XFS had important Ext4 features for years. Extents, delayed allocations, and whatever else is under the hood. What Ext4 *still* does not have: mount-time quota scanning and activation. It is so much faster than quotascan and safer because there is no window between mounting and turning quotas on (where a user could dump a huge file to gobble up space for himself).