I've always been more of a hummingbird fan myself. You could get the Helix 7 with SI and DI, GPS, Chartplotter and you can use the navionics lake chart cards with this unit as well. Also, you can get this unit for $590 taxes included and can be shipped to you within 5 days. Bass Pro sells them for $699 with a $100 rebate if you get a bass pro card. But then you still have to pay taxes on that $599. PM me if you want the sellers information, I bought from them and they are very reputable. I'm not a seller or anything, but don't want to violate any advertising rules on this site.