Get Size of All Folders in Directory

Add -maxdepth 1 to your find parameters.

Why use find at all and not simply glob for directories?

du -shc */

This one should do the job efficiently :

du -hc --max-depth=1

One big difference I think of is that, when encountering hardlinked files, they will be counted only once. In a find loop, they will be counted once per base directory. [Is it correct english?]