I have had K Planes on several boats.. all offshore, saltwater applications.. I really think they are perfect.
Add ons that would be kinda cool (might already be a thing) is a way to see degree of trim tab plane (much like trim on motors) on vessel view and maybe integrate that to GPS over NMEA.
I have installed the 380S version during the refit of my Marlin 350 FS with digital integration (via active trim control module and wiring harness - then they show a similar position as the motors in the vesselview).
Used them a few times at choppy seas or ballance load, so far they are awesome.