I'll throw in my 2 cents..... on the side imaging - it doesn't really cover a great distance, so in my mind it's not really worth the price for open water Lake Erie... the unit with downscan and Chirp will show you some great detail for perch fish, and show you the walleye as well. More 2 cents - I'd stay away from Lowrance - I'm still hearing nightmare stories about piss-poor customer service in the event you have any problems with your stuff.

Hoping Juls chimes in on this - she's a Humminbird freak! She can give more details on those features.