Although being very open to modding one or more of my Solo's makes me less concerned about 3DRs dropping development, I'll admit that matching the overall density of features of the Mavic just ain't gonna happen. And while we're pretty much stuck with the GPH4 if we want to retain full camera control, I'm not going to kid anyone that my skills are being restrained by that, I'm not that good of a photographer!
But I definitely see the attraction of the Karma and Mavic. In either case, but more so with the Mavic, I'd be concerned about reparability, there's just an awful lot of integration there, so if one thing goes wrong or is damaged, chances are high that it'll be a total loss. The promotional video of FPV racing it is kinda absurd - yea, you're really going to FPV race a thousand dollar drone... And while the size is great for transportation, I do question how well it'll handle wind when it comes to capturing smooth video. I could very well be wrong, but it seems to have a bit of a personality conflict - what's it's purpose? Racing drone, photography platform, highly advanced toy? Maybe they've pulled off all three in one product, and if so, I'll be very impressed.
Karma looks real nice, and is probably the obvious choice if video quality is your main concern, it's small enough, the support of the Hero 5 will ensure a longer useful life, and the detachable gimbal is great, again, if photography us your thing.
For me, my purchase decision is made too - none of the above! Solo and the Hero 4 far exceed my own capabilities, so unless that changes drastically, I'm good for at least a generation or two. I've always tried to make my equipment pay for itself, so until I start making money with these things, what I have now will serve my needs just fine. I try not to chase the latest and greatest, so if or when I'm in the market for another drone, it'll be a Karma 2 or Mavic 3 or something that's not even on the drawing board yet.