I am a very 'techy' guy, (nerd) and Raymarine's user interface is really abysmal. and drives me mental. just one example, I've never had any other device that has a 'home' button on the screen and a 'home' button with the same icon that do two different things. Just idiotic. In addition, if you try to go 'home' sometimes the damned thing just sits there and beeps at you. Awesome!
On RM systems I've actually used at sea, once you start really using them you do get used to how they want you to do it, but honeslty it's counter to every other electronic device I've ever used in my life. Most have more than one way to do something, with Ray there is usually ONE path to navigate the menus and it's usually not the one a 'normal' person would choose.
*in my opinion.*
In addition, they nickel and dime the hell out of you buying $60 or $90 proprietary interface cables and actually integrating and installing them gets annoying real fast. You can plug a B&G into a maretron or Garmin sensor and it will work. Not so with RM, you have to adapt their BS 'NG' crap to a standard NEMA 2k and as an Internet guy that also just really offends me.
I totally agree with you on Navico's insufficient information available, but in my experience they under-promise and over deliver. On a sailboat the new lower prices on Zeus make them a no-brainer.
The other benefit you didn't list is that the broadband radar has MASSIVELY less power consumption, another 'no-brainer' on a sailboat. Again, IMO, FWIW.