> How much cleaner can one expect one's ketone to get using one of these?
Depends on too many factors to give a definite reply.
> Will the distillation temp go down?
No. Usually it will go up when using a column. Not much at all using vigreux, but quite considerable with one of these.
> Do you need a variable reflux ratio distilling head or
> any complicated distilling head other than the 3-way
> still head
No, you almost never really 'need' them unless you want to produce ultra-pure solvents, although they can be helpful in certain cases. For small scale ketone distillation they are unnecessary or even counterproductive.
> Is this column really worth it?
For ketone distillation? No. Biggest disadvantage seems to be the big holdup, it will reduce your yield.
I'm not fat just horizontally disproportionate.