Well, there are 3 chart types really -
Navionics. Bluecharts and
Cmap. I haven't seen too many
Cmap devices, so that's pretty much out.
Between
Navionics and Bluecharts, I personally liked
Navionics because of the larger coverage. However it looks as though Bluecharts do better in Bahamas - they use Explorer
charts instead of the usual government stuff (and I read a few people complaining about
Navionics being way off). In the end, though, I don't think any chart will ever be perfect, so that's just one part of the equasion.
I am leaning the
Garmin way now (since I realized
Raymarine makes you buy
gps sensor separately - I think this is just a cheap trick on their part).