I work in the music industry. I got to take home a Quad Cortex in the fall before the units were fully baked. The software was super beta and there were no presets on the unit, but I'm convinced it's going to be the real deal if Neural can iron out the production kinks. Surprisingly, the high-gain tones didn't do much for me (again, total pre-release). But what floored me was the mid-gain AC30 model with Alnico Blues. It definitely delivered something I haven't found in thousands of Kemper profiles — sort of a midrange forwardness and response speed that I don't think I've heard in any other modeler.
Then there's the ability to use full-length IRs (which have come a long way in the last 9 years since they Kemper's debut), stereo rigs and cabs, the reduced form factor, and the freedom to work untethered from a computer. I'm waiting on the official launch, but I have little doubt it's going to be able to deliver on 90% of its promises.
My wife DID point out that she'll miss the look of my Kemper (she calls it my spaceship) if I trade up. Those of you who pre-ordered, I think your patience will be rewarded.