Yeah, pretty wild.
Once it's official it will be the fastest civil transport in service beating out the Citation X by a small margin. MMO on the G650 is .925
Coolest thing is that long-range cruise is .85, 7000nm range at this speed! And a 5000nm range at .90! This is what they're saying anyway, we'll see what the real numbers are, but this is Gulfstream we're talking about so I'm sure they'll be pretty close.
Not to mention HUGE windows and a 2600ft. cabin altitude at FL410, 4800ft. cabin at FL510! That's a huge advantage.