The gpu's are weaker than my 7870, the PS4 has the same number of SP's but is clocked at 840mhz instead of 1ghz. while the xbox one is comparable to an underclocked 7850.
So for project scorpio to be rated at 6tflops instead of 1.5 of the XO is a large jump. But pretty much just mainstream performance now in terms of pc hardware.
It isn't out until November 2017 though so by that time 6tflops wont be seen as that impressive ( thought still looks good for a console though).
Remember we have a "mid range" card, the 1070 out now which has 6.5Tflops.