Man, I wish you lived closer. I’d take you to the range and just let you decide there.
For pure shooting, the King is hard to beat. That said, I’m looking at the Night on my desk right now. I am comfortable with 6 135 GDHP +Ps out of these guns. Keep in mind that you are pretty much stuck with SP 101 leather for these guns for now; there’s just not that much kydex support out there. The K6 has way more options—odd, but true—although the 3" is harder to find kydex for.
I’ll be the voice of dissent on the K-frame: all three of the guns you are looking at are noticeably smaller than a K-frame. And I was a die-hard K frame guy for 3 decades, mind. There are *plenty* of posts here with me bragging on them. There’s just no getting around the fact that my 3" RB model 65-3 makes both Colts and the K6 look absolutely svelte, though. I see all three of your contenders as being in a different size category that splits between K and J, but actually leans a hair closer to the J. JMO, but as you know, I’ve compared ‘em all directly.
Lastly, I know that Kimber CS is reputed to suck, but at least they’ve fixed the couple of P-Fer owned K6s that broke, and upgraded the design; that’s a lot more than I can say for my last S&W buy. That’s “last" as in: both the last one I bought AND the last one I will buy; I’m done sending S&W wheelies back to S&W more than once, with no joy received.
I don’t have a ton of rounds through my King, but right now the only thing keeping me from being married to the King Cobra is the glare coming off the back of the frame curve that washes out the rear sight. If I can get that sorted, it’ll be the one for belt wheelies.
Right now it’s the Night Cobra.
JMO, OMMV, etc.