[_zamorano_]

Didn't try AltWinDirStat, but did try FastWinDirStat.

The thing is, FastWinDirStat uses a licensed propietary component. No problem for me, but the author did have some back and forth with another user on GitHub.

Seems FastWinDirStat license don't match with using a closed source library, or something...

As for its actual functioning, it does as it says. Works much faster than WinDirStat

[actionfromafar]

Looks like a pretty clear violation of the WinDirStat license. They took WinDirStat which is GPL, linked it with some other proprieraty code and distributed the result.

(They could have been clear-ish (with caveats) by distributing only the source code and let the users do the compiling and linking, similarly to how you could download ZFS and build it into Linux. But you mustn't distribute the result further.)