Very happy with its sharpness and colors. Could be a tiny tad sharper, but what it delivers is plenty.
HPX250 will be sharper, no doubt. Whether it would be sharper after the adapter got through with the image, is debatable. Someone will have to try it to see. But that's a substantially more expensive combination, than using an AF100.
Maybe.... but some of the tradeoffs include; a few stops loss of light, more setup/breakdown time, less portability and the need to buy more accessories. I used to loved the results I got with the HVX200+Redrock Micro adapter... but the AF100 makes shooting the same kind of content so much easier that I'm willing to trade any advantages offered by any fixed lens camera... YMMV.
I too debated this, and have spent quite a bit of time trying to match the kind of look that my Letus setup gave with my AF100. It can be done it just takes a little work. I think the AF100 has advantages that make it worth it for sure. That's not to say it still wasn't tough giving up the adapter, but I'm learning how to get this AF100 looking how I want. After my tests I've been able to get something indistinguishable from my old setup, with greater performance in the light department, lower weight, same Nikon primes, etc.