Sounds to me like the real key to this discussion is "back-ups". Multi or stand-alone...either way if only "part" of the system fails, you're still without that function. I like the "neatness" of a multi-unit and I'm a bigger fan of the "less = more" approach to all things electronic. Having said that, I keep a handheld GPS
, handheld VHF
, handheld Compass
, paper charts
, etc. on board. The only thing I'd really lose is wind related measurements and I've always got the 'stick a wet finger in the air' plan.