The actual process of switching was stupidly easy. I powered up the 430W, recorded the settings, shut it down. Pulled it out, replaced it with the IFD440 (same tray and connections - plug and play - zero wiring) and powered it up. Entered the old settings into the IFD440, and it just worked, right away. 20 minutes start to finish, no muss no fuss. Went and shot several approaches (VFR of course) to verify, and life was good.
the IFD 440 is more intuitive to work with, in my opinion than the 430W. I had to memorize certain key combinations on the 430W for shortcuts that are just obvious on the IFD, and they make flightplan modification very simple in the air with the ability to add airways or waypoints visually.
I have never used the keyboard - one more gadget to lose or kill the battery on, and it's not needed. I've got two airplanes with IFD440 and we're about to change a 3rd.