I have 2 HDS5 units linked together via ethernat cable. They are great units. Trouble free and fairly easy to use once you get use to them. For mapping, the Navionics Gold or Platinum card are ideal for the Great Lakes and Trent System. For inland lakes(Kawarthas, Muskokas, Nipissing, Temagami, etc) the Navionics Hotmaps Canada is the card to get. Some of the Kawartha Lakes are in HD which means a lot more contour lines and other useful detail. With the rebate offer going on now, you can't go wrong with the HDS series. There are ice fishing packs that Lowrance makes specifically for the HDS series. Good Luck.