I think it has the potential to be great IF they can get gear gaps and tuning correct.
This. How long did it take GM to get the 6 speeds tuned decent? Did they ever? I hated the stock tranny tune on my 2013.
From what I've read it CAN shift as fast as dual clutch transmissions but with GM's inability to tune a transmission I doubt we'll ever see that in the real world. Also, I don't know about 8 gears, the 6 speed seems to be a good mix of amount of shifting and gear spacing. My mom has a 14 Jeep GC with the ZF 8 speed in it and it seems that all it does is shift.
Do we know what kind of shifter GM is going to be using? There was talk when the K2XXs came out that they'd go electronic when the 8 speeds were rolled out after everyone on the internet did their normal bitching about the column shifter.