All I can say is I really, really like my Lowrance HDS 7 Touch. The maps of Lake Ontario are super detailed, with 1 to 3 ft contours.
Very easy user interface, and great unit all around.
Yes, it's outside of the budget, but you can probably pick up a very good condition, second hand Gen 2 HDS 5 for around$400, and probably an HDS 7 for around $500 to $600.