I haven't been using for a long time but it did help bring a packet rough and smooth trick back to
life.
It isn't friction based but it allow for easier separation than some other roughing
methods.
It is a good roughing tool, but some may prefer older methods this is more modern
take that has some good applications.
So far it seems once you separate you would have to
reapply the roughing cube to use again.
This could be an advantage but for most it would
mean extra work.
Recommend as a roughing tool for your toolbox.