In my usage, with IQ180, IQ280, and IQ160, and IQ260, sensor plus does give you more dynamic range in any ISO setting past 200, and in some cases, even better than 200. Even in good light, with 400 and 800, you will start to see loss in color saturation and shadow range. In low light the loss in both is extreme and the sensor plus files will be superior in all respects besides resolution.
I can see really no reason for Phase to use Sensor plus with their CMOS tech, as the main reason for sensor plus is for lower noise @ higher iso albeit at 3/4 loss in overall resolution. To cripple a 100MP back down to 25MP, when the images so far @ 400, 800, and 1600 are quite good, vastly superior to any CCD back I have used over the years, makes no sense. At least to me. You then open the entire discussion to lets compare the output from 100MP CMOS 25MP to a DSLR/Sony, Nikon etc.
Sensor plus was always a loosing proportion for my work, and I really never used it, as the resulting loss in overall resolution was just too much, where as if it could have been done by only a 1/2 loss, it might have been a great solution.
Paul C