The most popular brands used on Lake Erie are Lowrance, Garmin, and Hummingbird. I am a Lowrance man and have been very well pleased with Lowrance since the late 70's. I have friends that are quite happy with the other two brands. IMHO Hummingbird has been a technology lagger for the past several years but I believe that is changing now. I was very impressed by a Hummingbird presentation at a local sporting goods store recently.
One thing that has to be sorted out before you purchase anything and that is whether or not you want a combo unit with sonar and a chartplotter or separate units. If you have the dash space I would get separate units.
You will find now if you don't already know.......that the manufactures only support their products now for a year or two. So buy a recent model and get the maximum support time.
I can't speak of recent models because they do not get on my radar until I need a replacement. Get a unit that has an external gps antenna, no built-in antenna's.
Shop price, comparing features that you "want".
Good luck!
Terry