A screeding system for use with a screeding machine during screeding of an uncured concrete surface includes a control and a plurality of sensors. The sensors are disposed at the screeding machine, which has a screed head assembly that is movable over uncured concrete to screed the concrete surface. The sensors include elevation sensors that sense an elevation of the screed head assembly relative to a reference plane established at the concrete area. The control processes data captured by said plurality of sensors while the screeding machine is screeding the uncured concrete surface. Responsive to the data processing of captured data, the control estimates a flatness or levelness or quality of the surface of the concrete being screeded. While the screeding machine is screeding the uncured concrete surface, the control generates an output indicative of the estimated flatness or levelness or quality of the surface.