Does anyone here have one of these cheap aluminum CNC t-slot tables off eBay?

https://www.ebay.com/itm/T-Slot-Tabl...0AAMXQUmFSiQmp


How are they? Are they cheap because they are poor quality or are they just good value? Did they arrive suitably flat out of the box or do they they require a whole bunch of hand-scraping before they can be used (with accuracy)? Are they stiff enough to use as a moving table (on a fixed gantry machine) or do they require a seperate (thicker) base to mount them on?