PolyTany,
you accuse someone you don’t know in having interests in other plugins and yet claim the other person is “unfair”. May I stress out that this is none of your business and I express my opinion as allowed and encouraged by WordPress?
I am/was upset that the author does not clearly delineate free from paid, not because he has also premium version of it. I have bought bunch of paid plugins and would have probably bought this too, but don’t like surprises generally, not speaking of the fact that disabling the other cache, moving to this, returning to the other one broke my whole site, caused 2 hour downtime before I could restore from backup.
That said, I might still test the plugin’s free and paid on another site of mine and might change my review up.