NEC's SpectraView is somewhat unique in that it's the only solution that has access to NEC's internal calibration hardware that they don't let 3rd parties access. And, of course, being able to use the internal calibration hardware is a big deal, but only for those with NEC displays. For non NEC displays, Color Eyes Display Pro, BasICColor and Spyder3Elite are all pretty top notch, IMO, with iterative calibration and full white point control.