Grandperspective seems to be working very fine on OSX. I like the NCurses ncdu very much as a more general solution since it works in my mac but also on my servers.
I like PA Storage Monitor on Windows - lets you find large files, files of a type, disk hogs, and (what I like most) lets you compare folder sizes over time.
There is WinDirStat (https://windirstat.info/) on Windows and quite a few similar tools on Linux such as Baobab, KDirStat, etc... (http://www.makeuseof.com/tag/how-to-analyze-your-disk-usage-...)