I have a REAL issue with things not being flat, square, and true so the accuracy of this table suits me. If some would rather shim and jigger their stuff together on some half warped rusty steel table more power to them.
I wasn't trying to be a downer on the topic, just stating the facts. The Rhino Cart ad does say nitrided top, reversible? Why someone would want to reverse their welding table top escapes me. Now, other than the fact that the table specs state .004" in 12", what are the tolerances across the width and length? This would be the same as saying; My surface plate is accurate in this quadrant. The table tops are offered with or without the nitride treatment and the treatment is about the only thing that's going to maintain the tolerances or specs when the tables are being used.
In regard to flat, square and true..................You can't purchase a piece of material that's precision, or even close to those tolerances unless you go to a specialty house, then after you weld on it, it isn't going to be flat square or true. At some point in time, after the tacking is all over, you have to remove the weldment out of the fixture and weld it up. I understand that clamping is one form of controlling induced stress and distortion, but emphasis is controlling, not controlled, because you can't.
I believe in truth in advertising so I would like to see the weldments featured in the Rhino Cart ads or ProBuilt welding tables turned around and fixtured up so the opposite side can be clamped and welded. I'm sure the point in some of the videos are to show the different clamps available (that's their money maker), but many show setups that limit tacking and welding.
I know these tops have become more popular with individuals over the last few years but they are mainly used in production assembly lines for robotics. Marketing says lets sell these to Joe Public, they're cool, along with the professionals always use half warped rusty plate.