Well it's definitely a ball screw/ball nut which should be better than a leadscrew/trapezoidal nut. However it does seem a bit cheap, I bought some of roughly similar dimensions from BST (known good vendor on here) a year or 2 back and they were a lot more than that. You might get lucky or you might need to buy 5 to get one good one. In the end if you're trying to make an accurate, quality machine you need decent parts, no way round that.