I had a 2015 Honda CBR600rr that I sold in 2018 to get my N1k. I loved my CBR600rr. Still do (my friend owns it now). I miss it's lightweight handling, and its electric motor smooth inline 4 that revved to the Moon.
Having said that, I'm over it. I want to be comfortable all day long. The Ninja 1000 is that bike that is a sportbike first, comfortable sport-tourer second. She looks, sounds, and feels sporty. Her gearbox is a close ratio (just like your ZX6R). Her brakes are strong. Her handling is super stable and relatively flickable. Yet she is all day comfortable. She protects you from the wind. She can carry bags. She can go long distance without torturing your body.
I test rode the Ducati Super sport and the Suzuki GSXS1000f. Ducati was not even close performance-wise. Just didn't have the motor. Not slow. But slow compared to the N1k. The Suzuki is close...very close....and faster on top. But the Suzuki doesn't have the features of the N1k. And it's just damn ugly.
Honestly, I don't miss my CBR600RR. There's never a day when I wish I had it back. I watch my friend ride my old CBR, and he loves it and I'm glad. But I have no regrets. I can keep up with him easily on my N1k. And when I see him stretching and aching after 150 miles, while I'm still good to go, I know I made the right decision.