If you use a Btrfs filesystem with snapshots, I can recommend Btdu as an alternative. Advantage: Can handle duplicate files (snapshots), which however only occupy 1x disk space.
> btdu is a sampling disk usage profiler […] Pick a random point on the disk then find what is located at that point […] btdu starts showing results instantly. Though wildly inaccurate at first, they become progressively more accurate the longer btdu is allowed to run.