The one positive that intrigues me is that they supposedly show shallow water that the others(g2, etc) do not map for whatever reason. That being said, I have been looking at Lowrance and Hummingbird compact models that only accept Navionics Gold but not Platinum.
Don't waste your time and money on any cards other than Platinum + and the newer units which satisfactorily display these cards if you are interested in detailed inshore info. I have tne Navionics fish N chips, gold card, Premium South and none give details on inshore Englewood, Bull Bay, the Everglades or LA marsh on my Lowrance LCX 28. I talked to Navionics last week and understand the micro sd cards do give the contour and detail inshore but require newer units to read them .
I have been thinking of getting a Navionics card for my Humminbird 798DSi. But the info on the website is so vague. They dont really show you what you are getting. Or what all that it actually covers. Best that I can tell, the areas that I fish are not mapped in detail. Lack of info has me put off... Anyone know where I can get better info than the Navionics website?