Done a bit of time in 5.2m KCs, a big trip in a 6.2KC, never been in a 2400KC, a bit of time in a 3100NC, a quick lap in crap in 2700NC and a fair bit of time in a Grady White 26' Tiger Cat. The Tiger Cat felt like a 30' or bigger deep V mono game boat for ride. Just a small lurching motion, no boof and bam like the Aussie boat, even the 3100 which still feels like a big trailer boat. That said, I rate them all. I'd say a deep V 30' game boat or bigger with twin diesels would ride smoother than all the cats but you have to get up into that 30' size to have any advantage over a cat then the deep V monos take over. I can remember heading out one rough day in a BW34' with twin 270hp diesels and we did it easier than a 37' KC with outboards. I love the little 5.2KCs, the 6,2s are better with the extra length and I nearly bought the 2700NC but couldn't quite stretch that far. I'd love to try a GB or World Cat or whatever to compare as well but also the industry standard 2400KC. I've got a feeling the KCs will outperform a NC for the same length though.