Lowrance has major nav aids put into it and they take a little more care when mapping land masses, but there in no bottom comture data please don't buy based on my humble opnion, I have spent many hours working part time as west marine and hours playing with these units, I have seen and used most of them on one kind of boat or another. but, everyone has there personal preferences, go to west or boaters world and spend some time playing and looking, *the folks at either one should have lots of answers and should be happy to let you play for hours on any unit the have.