Just a quick question, what are advantages of bearings over bushings? I am designing a small combination of cnc(mostly wood/plastic) and 3d printer ocessionally. I am choosing between this 10x SF 1 Self Lubricating Composite Ball Bearing Bushing Sleeve 12 x 14 x 25mm | eBay and this 2pcs LM12UU 12mm Shaft Linear Motion Ball Bearing | eBay