+1 to @Janello, you get what you pay for, invest in a good one and be done with it. also use a good straightedge that you can ride the shoulder of the cutter on and score only once, tape the straightedge in place if you have to, especially on long cuts.
the front brush, near the dust collection hood came out easy, the rear one behind the vent on the rear of the machine was stuck in there. they are held in with a small clip and removed it with a needle nose pliers, blew it out with the air compressor cleaned the armature and brushes with alcohol on a swab and soft cloth, reinstalled and walla! it worked
Yes, being that far out of square or leaving sanding/chatter marks behind is definitely sub standard, at least for proper furniture.
But this rustic/reclaimed trend has unfortunately brought with it a lot of sloppy work that people seem willing to tolerate.