Navionics/Depth Finder question

I tried to update my Navionics mapping card online. It appears its to old, doesn't have enough space. I think its just a little over 500 MBs. I looked into ordering a new one. However my Lowrance LMS332 isn't compatible with the new card. Are there other manufacturer's out there I can order a mapping card through?
I've considered a new depth finder but I'm not liking the reviews on the Lowrance units with side scan. I don't mind going to a Hummingbird or other unit. Need some input on whats working and whats not?