Tried 'Big Mean Folder Machine" before finding this little app. And now I'm amazed at this small, spiffy, light and very well-written piece of code.
"Folder Splitter" no-frills, no complicated settings are an invitation to keep it like one of your favorites tools.
I use it every week and until now see no problem or hassle whatsoever.
The only 'catch' is that you HAVE to create a new folder (with an indifferent name) just to be the target of the splitted folders - it strangely cannot split within the same directory (the same folder that contains the original big folder).
Aside from that, this is a program that relies on your Mac's processing and HD speeds and quite useful.
It delivers what it promises. Did I mention it is fast?