Review on MGN12H Sliding Carriage Printer Machine Power Transmission Products by Sheppard Priest

I ordered 4 of these and received 4 guides made by 4 completely different machines/people/company. 1 of these are excellent, high quality, clean bearings, properly lubricated and much more than I expected for the price. 2 of them are fine with some roughness. Both need a good cleaning and lubrication before use, but work well and are still good value. 1 of these is hot trash with mismatched metal balls, poorly made track, bad wipers, no oil hole etc and now it's in the trash. I would send it back but I don't know what happened and I don't want to penalize 3 people who sent me acceptable products. It's very difficult to write a consistent review of basically 4 different products.