I have actually purchased ball screws from Linearbearings through Ebay some time ago,
I have found the product to be extreamly good for the price and zero backlash. I fitted them to a 9x20 lathe which I retrofitted to cnc and the repeatability is excelent. I would definately buy them again. The shipping was around 2 weeks to Australia. The funny thing is I have Thompson ballscrews on my cnc mill, they sound crunchy and have approx .004" backlash, mind you they are the budget model (which is still triple the price of the ones from China)
. I will be soon fitting the Linearbearings screws to that machine as well. Here is the link to the store.