A lot of the DIY machines on here are built with Chinese ballscews, ballnut and linear bearings. Do you have evidence the ones in the 6040 are inferior? The rest of the structure is metal and screws, probably machined on very good industrial kit.

I'm not saying the 6040 is a perfect machine but I think you are going way over the top with your comments in the context of a small run machine for wood parts or light aluminium. Yes DIY will give better results, but only if you are willing and able.