I purchased the Lake Master chip for Wisconsin but I did not do enough research before my purchase. I spent my time researching the GPS/depth finder, a Humminbird 5 series, which I am very happy with. The purchase of the Lake Master chip was kind of an afterthought and now I regret not putting in more time researching the chip. After all, if the GPS chip doesn’t have the lake you are on you’ll be looking at the outline of the lake with the lake being all blue (no contours). The only help the GPS will be to you then is to help find your way back to a fishing spot or back to the boat landing. For my use I am disappointed with the selection of lakes on the Lake Master chip. But the same lakes I am interested in may not be important to someone else. One example is the Rainbow Flowage in Oneida Co. The Lake Master chip does not have this flowage where the Navionics north does. There are many more examples if you compare and it also seems like the Navionics has more Wis maps as well as Michigan, Iowa, Minnesota, N. and S. Dakota where Lake Master chip Wisconsin is almost exclusively Wis. Minnesota and the Dakotas are each separate chip you would have to buy. But what I don’t know is what lakes are High Def. And if cost is important the Navionics is priced at ~$75 more than Lake Master. My suggestion to anyone looking to purchase one of these is to make a list of lakes you want on the chip, search the lake lists, and then consider whether high def is important. You may find lakes you are interested in are not on either chip, one chip has the lake and one doesn’t, each have it but one is High def and the other isn’t, or both have it in high def. As for which one is more accurate, reading the blogs it seems like each one can claim to be more accurate in one area or another. I’m not sure how to research this. Good luck to anyone preparing to purchase a chip. I hope you are more prepared then I was.